I know there are a lot of lists out there like this. Well, here is another one, maybe with some things you haven't thought about before! Keep in mind, these are suggestions and are not "rules" in which you must follow.
- Buy a wig. Wigs really help to put the final touches on costumes. Specially costumes where the character has odd colored hair or a weird hair style. Even if the wig is a cheaper one, it can still be better than no wig at all.
-Tailor costumes so they fit your body. Costumes, just like your everyday clothes, don't look good if they are too big or too small.
- Iron your costume! Or steam it. Whatever is best for your material. If you can't do those, toss it in the dryer!
- Wear dancer tights or stockings with short skirts or costumes that reveal a lot of leg. This makes your legs look very nice and smooth and you won't have to worry about if you missed a spot shaving or that your legs are really pale. (Like mine!)
- Think about what the weather will be when you wear your costumes. This is more based on temperature than anything else.
- Wear a little make-up. Even if it's only a light foundation or some eye liner.
- Clean your costumes. Dry cleaning, hand washing, throwing it in the washer...whatever it calls for, keep it clean. If you wear it on more than one day during a con, hang it up and air it out, maybe fabreeze it.
- Wear sneakers with every costume. If you are having show trouble, hit a thrift store or try making show covers. Nothing ruins a really nice Sailor Scout uniform like a pair of sneakers.
- Claim work you haven't done on any part of costumes. It's very rude.
- Forget to take off your glasses for pictures! We've all done it, sometimes it's because the person taking the photo didn't give you time, and others we just don't remember to.
- Throw your wig down in some spot and leave it. If you have wigs, taking care of them isn't very hard. If you don't have wig heads. lay them out on a flat surface so they don't get tangled up.
- Forget your manners when in costume. Be polite to other people around you, remember, kill them with kindness.
Well, that is all I can think of for now! Feel free to comment with other suggestions!