Guidelines For A Superhero Wardrobe Designer to Live By:
 1.  I will not dress my superheroes in skin-tight uniforms. Aside from cutting off valuable circulation, being able to see every line and muscle on your hero equates to those same muscles being severely restricted of movement. Looking hot does not count for much when you’re being beaten stupid in a fist fight because you can’t expand your lungs.
2.  I will not let my superheroines wear heels that are four inches high. Better yet, I will make sure they avoid high heels entirely. Barring invulnerability or a superhuman sense of balance, this is a perfect way to ensure an embarrassing mid-battle stumble or a broken ankle.
3.  I will not let my flying superheroines wear skirts unless they are wearing shorts underneath. If any dispute this, they will be immediately enrolled in a course on Basic Common Sense.
4.  I will not let my male superheroes wear their underwear on the outside, especially if said hero is supposed to be of the very serious persuasion.
5.  I will not let my superheroines out of the lair with anything less than full-body coverage. Wearing a skimpy, revealing uniform while fighting dinosaurs and laser-wielding megalomaniacs is akin to motorcycling on gravel in a swimsuit: no one can take you seriously, and when you hit the dirt, it will hurt a lot more than if you’d been wearing your chaps and jacket.
6.  On the same note, I will not leave stylish holes in a hero’s costume over vulnerable areas, even if the hero thinks that he or she is invulnerable. To bare that muscular midriff to the world is to invite punishment from anyone who has an ounce of hand-eye coordination.
7.  If my superhero has a secret identity, he or she will be required to wear a mask while in superhero form. We will not be relying on the general dull-wittedness of the populace or the incapability of news reporters to get a good picture.
8.  Heroes may not grow their hair as long as or longer than their body, unless it is being used as a weapon. Aside from being a tripping hazard and a convenient homegrown handle for any enemy to grab onto, eight-foot hair is not contusive to maintaining a secret identity, as it tends to stand out in public.
9.  Capes will also be easily detachable, kept at a moderate length, and made of materials that are resistant to snagging. Practicality is not to be replaced with flair, and my hero is not likely to look very heroic if his or her cape is constantly catching on gargoyles or being yanked on by the enemy.
10. I will require my superheroes to be prepared for all weather. If a hero from California is going to fight Ice Mammoths in the Arctic Circle, he or she will be required to change into his or her Winter Uniform before departing. The reverse will also be required, barring the hero’s ability to not overheat while wearing furs in 100-degree weather.
11. Leather as a clothing material shall be limited to boots, gloves, capes, and jackets. If it must be used in a protective fashion, it shall be sewn on over proper clothing so as not to restrict movement or chafe.Â
a.  As a necessary corollary to the above rule, metal in uniforms shall be used only for accessories and protective armor, not as a replacement for clothes. Any superheroine caught trying to go out in a metal corset shall be severely reprimanded and enrolled in another course on Basic Common Sense.
12. All heroes will be required to have at least two or more copies of their uniform, and to hide them in acceptable locations. They will not be permitted to keep their one and only costume in their backpack, or worse, under their clothes at all times. Not only does this invite all manner of accidental discovery, it also shows that your hero lacks a basic sense of good hygiene.
13. When designing their uniforms, my heroes will regularly defer to a respectable fashion designer to ensure that their sense of fashion is not completely outdated, glaringly painful, or utterly impractical. No matter how original and unique they might wish to look, heroes who are wearing thirteen mismatching colors in five different patterns and styles are only embarrassing themselves and their local heroing community.
14. If a hero wishes to wear casual, non-tailored clothes with small or no personal logos instead of a complicated costume, they will be perfectly welcome to do so. They will not be ridiculed by their fellow heroes for having a selfless lack of need for fame and public adoration.
15. Heroes will abstain from adding frivolous and impairing special effects to their costume unless they can prove that these additions make practical sense. i.e. Nighttime costumes will not bear glow-in-the-dark stripes or phosphorescent trimming unless it can be turned off for stealth purposes, and helmets used in lu of masks will not have protrusions that impair the wearer’s ability to fit through small openings.
16. All costumes will consist of as few individual pieces as possible (that comply with the above regulations). This is only practical, since superheroing usually relies on timing, and you’re not going to make good time if you spend fifteen minutes fixing all of your belts and accessories before answering each call. There is no objection to these attachments being sewn onto the costume ahead of time for stylistic effect, but use common sense. Zippers are a wonderful and easily disguisable invention and should not be scorned.
  I wrote this up like a year or three ago, and I add to it every now and then. If anyone has any ideas for additional rules, feel free to add them. ;) I'll post again tomorrow with the addendum to this called "Hero Rules of Conduct".
(This list was written by me, Riverfox237 aka TheRIU. ^^)