So You Want To/Write a Humongous Mecha Anime

Necessary Tropes

 * Humongous Mecha - This one is pretty obvious, although you can use Mini Mecha instead.
 * Applied Phlebotinum - You need some form of explanation for why they're using giant humanoid robots/golems/biomechs instead of tanks and planes. It can range from "Getter Rays need a human form!" to "They're maaaaagical" and even more 'realistic' explanations such as Gundam's "Humanoid robots can turn around in space without wasting fuel". Careful with making these mecha more specialized - they may slide out of your series' focus.
 * Rule of Cool - Even the most Real Robot show operates on this, because if it were any more real, it'd just be using tanks instead.
 * Big Red Button - No mecha series is complete without one.

Choices, Choices

 * Real Robot or Super Robot? - Do remember that Real and Super are adjectives, and not strict delineations of genre; nor are they Power Levels. Super robots can have numerous weaknesses and drawbacks to usage, and real robots can be extremely powerful (ever hear of nuclear weapons?). They are best defined as settings.
 * Super Robot: Though Mazinger Z is the trope maker, Getter Robo is an example of pure Super Robot, it has a mysterious machine made by a Mad Scientist that is brightly colored and does very impractical things. Super robots are defined by the Rule of Cool, typically. And Crazy Awesome.
 * Real Robot: Gundam is perhaps the archetypical example of the Real Robot setting, with Armored Trooper VOTOMS taking it to the max. Real Robots settings typically have the mecha as mass-produced weapons of war, and oftentimes they're ignominiously blown away, much like soldiers in war films. See also Patlabor, an even more realistic series given that it's in a non-military setting.
 * Mix N' Match: Who said you had to stick to just Super Robot or just Real Robot? Dorks, that's who. Eureka Seven leaned more towards the Real side, but that didn't stop it from having Imported Alien Phlebotinum, The Power of Love and some awesome designs. Neon Genesis Evangelion was arguably more Super, but the mecha had power time limits and other drawbacks to them. Even Gao Gai Gar, a popular Reconstruction Super Robot show had many Real Robot elements.
 * Piloted or Remote Controlled? - Does your main character pilot the mecha (like in Mazinger Z, Gundam and most others), or is he or she The Kid With the Remote Control (like in Gigantor, Giant Robo and The Iron Giant) who controls the mecha from outside? How is the mecha usually piloted or controlled? And can the mecha act independently of its pilot or controller (more common in Super Robot series than Real Robot, by the way) if he or she is incapacitated?
 * What do your mecha do? Do they fly? Are they speedy and lithe, dancing pirouettes around bewildered tanks and infantry, or are they clunky and landbound like Battle Tech or Fang of the Sun Dougram? Are they mostly for space, like Gundam and Jovian Chronicles, or do they fight on planetary surfaces?
 * How large and mighty are your mecha? How powerful are they relative to other kinds of prominent fighting vehicles?
 * What kinds of technology are used? Just slugthrowers and sidewinders? Frickin' Laser Beams? Laser Blades? Cloaking? Funky mind control interfaces? Techno-organic building combiners?
 * What are humanoid mecha called? This is a twofold question. First, what's the general type name for anthropomorphic war machines? Second, what are the names of individual machine types? Here of course is the great dividing line between cool-sounding nonsense (Zaku, Gaplant, Dauzehn, Methuss, Gafran, etc) and real words (Heavygun, Rapier, Minuteman, Cicada, etc.)
 * If you really wanted to, you could forgo the crew/pilots and have sentinent humungous mecha. If you do decide to do this, though, try not to rip off Transformers.

Pitfalls

 * Falling Into the Cockpit can be done correctly, but sometimes it'll just come off as totally lame. It's a borderline Dead Horse Trope. Super Robot shows tend to do this better, since they're absurd to begin with.
 * Follow the Leader - As successful as Evangelion, Gundam, Macross, Getter Robo, etc. were, don't make the mistake of aping elements from them left and right. Originality is a nice thing to have.
 * Lensman Arms Race - If you're doing a staunchly Real Robot setting, don't pull this. This will probably just confuse your fans. In Super Robot, go right ahead... just do it right.
 * Gainax Ending - Goes without saying.
 * Square-Cube Law: A 50-foot tall robot will more than likely crunch! under it's own weight, and normal vehicles can outmaneuver them very easily. How will you get around this?
 * Conspicuous CG: Computer generated animation can be done well, but if done badly it will make the entire project look half-assed.

Potential Subversions

 * The Kid With the Remote Control - What happens if the remote control... breaks?
 * Power of Friendship/Love/Trust - What if it's not enough?
 * Rule of Cool - What if the ultimate attacks are Awesome but Impractical? What if the heroes can win by being sensible and practical, reigning in their Hot Blood? What if the bad guys are the ones who do things just 'cause they're cool, while the heroes take these life-or-death battles more seriously?
 * All There in the Manual - It can be really cool to have all sorts of fancy gadgets but it might not sit well with some people.
 * Gundamjack / Black Box - what if whoever makes the Super Prototype / advanced technology in question had the foresight to take out a patent on the design, making it worthless for reverse engineering purposes? Sure, it's just silly in war story (why would people on the opposite side of a war would care about patent laws, especially if one side are aliens?), but can be done on smaller scale, like corperations conflict.

Suggested Themes and Aesops

 * War Is Hell - As seen in Gundam and many of its successors. Be warned, though - anti-war stories are notoriously hard to do without making the fighting look exciting, and that's even harder when you have inherently awesome giant robots.
 * Green Aesop - Having all these seventy-ton death machines stomping around can't be good for the environment.
 * Screw Destiny - and punch it out with your Super Robot! Or...
 * You Can't Fight Fate - even with your Super Robot. Sigh.
 * Determinator - but keep trying anyway! Really, the Humongous Mecha can be useful in illustrating whatever quality you want to laud, especially if it runs on Aesoptonium. Also related - I Will Fight Some More Forever.
 * Becoming the Mask: These characters are often great sources of conflict. There's a reason why Gundam has so many.

Potential Motifs

 * Gambit Pileup - Nothing says suspense like loading on a huge convoluted plot to keep the audience guessing.
 * The Power of Friendship - A natural fit for Combining Mecha
 * Super Mode - Makes it easier and cooler to display Heroic Willpower

Suggested Plots

 * Gundamjack - Nothing says excitement/plot developement like stealing the protagonist's/antagonist's Super Prototype.
 * Villain Protagonist: Fear me and my giant robot of doom!

Set Designer / Location Scout

 * Twenty Minutes Into the Future - The most common place to set this kind of story. On Earth, but in the future!

Props Department

 * Rocket Punch - the original, iconic Super Robot weapon.
 * This Is a Drill - All the better to pierce the heavens with.
 * Attack Drone - Funnels, anyone?
 * Chest Blaster - BRESTOOO BURRRRN
 * Eye Beams
 * BFS - or any oversized melee weapon, for that matter.
 * BFG - There is always room for More Dakka
 * Beam Spam
 * Macross Missile Massacre
 * Mecha Mooks - useful for maintaining an idealistic tone. Usually.
 * Wave Motion Gun
 * Deflector Shields - Nothing says cool quite like Hard Light.
 * Plot Armor - Need your mecha to be tossed around some for great action, or to demonstrate how the character is so awesome? Look no further. Be VERY careful when used in conjunction with Real Robot.
 * Minovsky Physics - For Real Robot writers who want/need to inject some applied phlebotinum without loosing their sense of realism.
 * More Dakka - Attack Attack Attack!
 * Self-Destruct Mechanism - Useful Third Option for hopeless situations.
 * Cool Ship - For helping your Mecha get around.

Costume Designer

 * Latex Space Suit - A staple of the genre.
 * Scarf of Asskicking - Even on the mecha, if you like.
 * Caped Mecha
 * Cool Shades
 * Space Clothes

Casting Director

 * If Japanese, getting Nobuyuki Hiyama somewhere in there would be great. If American, Dan Green as The Obi-Wan or The Captain is a good bet, as Koutarou Taiga demonstrates amply.
 * For a Large Ham - Crispin Freeman is your best bet.

Stunt Department

 * Macross Missile Massacre
 * High Speed Missile Dodge
 * Roboteching
 * Point Defenseless
 * A-Team Firing
 * Deus Ex Machina
 * Deus Ex Nukina - Unless the Nuclear Weapons Taboo is in effect.
 * Fighter Launching Sequence
 * Old School Dogfighting - In Mecha form.

Extra Credit

 * If Super Robot, pack in some Crazy Awesome. If Real Robot, do it anyway.
 * Nothing says cool/profits like introducing a Mid-Season Upgrade. That's double the money in model kit merchandise!
 * Fun With Acronyms
 * Any mecha show can be made exponentially cooler with moar Techno Babble.

The Greats

 * Gigantor/Tetsujin 28 - The very first Super Robot series (and indeed, the very first Humongous Mecha series), featuring a giant robot and The Kid With the Remote Control who uses it to fight evil.
 * Mazinger Z - The Trope Maker for piloted Humongous Mecha and in many ways the codifier for the genre. If the original series is too dated, perhaps check out the 2000 remake Mazinkaiser or the 2009 version Shin Mazinger.
 * Getter Robo - The first Combining Mecha, and a very Troperiffic series that is the exemplar of the more psychotic variety of Hot Blooded. Try the Manga or the OVAs.
 * UFO Robo Grendizer
 * Zambot 3
 * Brave Raideen
 * The Romantic Robot Trilogy of Combattler V, Voltes V and Daimos.
 * Mobile Suit Gundam - An innovator in its time, it helped codify what Real Robot was.
 * Space Runaway Ideon - Directed by "Kill'Em All" Tomino, who lives up to his nickname here, it is about the Ideon, a Super Robot with a rather scary power source, the Ide. Was one of the inspirations for Evangelion.
 * Macross - While it wasn't the first Transforming Mecha show, its slick designs, catchy music, The Power of Love and other elements helped turn it into successful franchise.
 * Zeta Gundam - Took Gundam to the next level.
 * Armored Trooper VOTOMS - Votoms is the leader of what defines 'Real Robot'. The mecha are basically glorified humanoid tanks, and their main propulsion most of the time are wheels built into their feet. Instead of a kid, the main character, Chirico, is a hardened elite soldier who knows what he's doing.
 * Dancougar
 * Transformers - More than meets the eye.
 * Patlabor - A rare example of mecha used in a civilian rather than a combat setting, if you want to see how that works. Like Votoms, it is on the "very real" end of the spectrum.
 * Exo Squad - An early example of original Western Real Robot series, inspired by Gundams and set firmly in the Military Science Fiction zone.
 * G Gundam - a great example of how Humongous Mecha can be combined with any genre. A Chinese martial arts adventure with giant robots? Awesome!
 * Giant Robo - Both an old live-action series (with Giant Robo being a guy in a suit) and later an OVA series, which was directed by the same director who did G Gundam.
 * Neon Genesis Evangelion - Love it or hate it, Evangelion changed the genre forever. It created a whole new school of more organic mecha design, and subverted so many Super Robot tropes. It is the Watchmen of mecha anime.
 * Gundam Wing - The first Gundam series to gain a major fanbase in America, and in both countries, it introduced a new viewer demographic: Girls.
 * Zone of the Enders
 * Eureka Seven - the genre with its most badass action, greatest character development and one of the most excellently handled anime love stories of all time.
 * Rah Xephon - At first glance, it seems to be an Evangelion imitator, but it's actually a Spiritual Successor to Brave Raideen. It combines a musical motif with mesoamerican mythology to create a rich, alien atmosphere.
 * Megas XLR - A rare true American example of the Super Robot genre, made from whole cloth rather than by Macekreing an anime. Defined by Rule of Cool, Rule of Funny and Crazy Awesome.
 * The Big O - Batman with Mecha? Alright!
 * Gao Gai Gar - Helped make the Super Robot Genre cool again.
 * Tengen Toppa Gurren Lagann - in case you don't want your Super Robot to fight one Monster of the Week after another, you can turn to these for good examples of lighthearted Super Robot adventure series. Gets darker later on, though also more awesome.
 * Combat Mecha Xabungle - Who says a Real Robot series can't be a lighthearted adventure? Certainly not this series.
 * Macross Plus
 * ''Gundam 0080
 * Mobile Suit Gundam The 08th MS Team - Notable for playing most Real Robot tropes extremely straight for a Gundam series.
 * Gundam X
 * Turn a Gundam
 * Fafner in The Azure - Though it starts off fairly slow, it's well-paced afterwards, and uniquely the focus is not entirely on giant robot battles. If Neon Genesis Evangelion is too disturbing for you, this is a more stable and melancholic alternative.
 * Bokurano - Good mixture with Cosmic Horror Story.
 * Gundam SEED- Say what you will about its sequel (see below), Seed repopularised the Gundam franchise and brought in a whole new generation of fans to Gundam. It also adapted parts of the original Mobile Suit Gundam storyline, while still managing to tell an original story with likeable, sympathetic, and above-all, well-developed characters.
 * Full Metal Panic - The mecha are not really central to this one. What makes it enjoyable is the character interaction. Writing interesting characters is vital to any good story.
 * Gasaraki
 * Code Geass - Death Note with mecha? Alright!
 * Gundam 00 - This series subverted or outright avoided many Gundam tropes and developed the Political aspect a lot.
 * Macross Frontier - Took Macross to a whole new level. Just make sure you don't get your Humongous Mecha series in a sticky legal situation with American distributors though. Harmony Gold is notoriously responsible for preventing this series from reaching American shores.
 * Gundam Unicorn
 * Martian Successor Nadesico parodies the genre by placing Super Robot characters in a Real Robot setting.

The Epic Fails

 * Gundam SEED Destiny ... it certainly has a huge hatedom. If anything, it's greatest failure(s) seem to lie in the fact that all too often, personal conflicts between cast and crew would spill over into the story itself. Whether you like this series or not, don't let this happen.
 * Zeorymer, which never seems to realize that the Designated Hero is possibly one of the only instances where the Wangst-ridden Extreme Doormat personality is actually more likeable than his "badass" self. To say nothing about being the poster child of unstoppable heroes of the bad kind.
 * Astro Plan, for being a ripoff of the most shameless order.
 * Candidate for Goddess / Pilot Candidate shows us why blatantly ripping off other mecha, such as Evangelion, and providing a weak Gecko Ending can be very, very bad for your show.
 * Super Dimension Cavalry Southern Cross is not really spectacularly bad so much as uninteresting to the point of being a cure for insomnia. Reportedly, the Japanese reaction to the "Southern Cross" segment of Robotech was along the lines of "How the hell did they make Southern Cross watchable?"
 * Space Thunder Kids shows us all why having a plot is important. Battle scenes are all well and good, but they have to be meaningful. Don't just use Stuff Blowing Up to pad a thin script. Also, Plagiarism is bad.
 * Battle Tech's animated cartoon was an attempt to take a popular video game and tabletop wargame franchise and bring it to television. Unfortunately, an astounding lack of research and clumsily rendered animations led to mediocre results at best. Be mindful of your setting and prior fan expectations if you're going to do an Animated Adaptation or similar derivative work.