Happy Halloween! In the spirit of Halloween, I want to talk about- cosplaying. Cosplay (コスプレ kosupure), a portmanteau of the words costume play, is a hobby in which participants wear/make costumes to represent a specific fictional character.
I've been cosplaying off and on since 2008, mostly with friends or classmates. By no means am I a proficient cosplayer-- I have never done any photoshoots or professional modeling, and all masquerade skits I've been in are... admittedly crap. Therefore, I do have much more experience on how NOT to cosplay.
1. Don't procrastinate.
This is a given (and for anything in life really). But procrastinating, especially if it's for a convention, photo/video shoot, gathering, or performance, is going to result in a crappy cosplay. This applies even more if you're making a new costume altogether. (Ordering online very late can be bad as well- who knows what may happen during shipping.) It usually takes a lot of time to complete a full cosplay that's good and will not fall apart or look terrible.
2. Don't splurge on homemade supplies that you'll never use.
There is a myth that making your own equipment will always be cheaper. Yes, that can be true, however if you don't know how to make use of them efficiently, it could also result in weak quality and fall apart. Not to mention- if you give up on it, you now have accumulated useless half-completed crap.
3. Don't forget to research your character.
This mostly applies in certain conditions- if you cosplay a character you know and love, you have nothing to worry about. In group settings, it will definitely show when you don't know how to pose, don't know how to act, and don't know certain references. You don't have to suddenly become an obsessive fan, but some quick wiki research never hurts.
4. Don't destroy things during a skit.
The reason is fairly obvious: breaking things onstage is bad because of potential injuries, stage damage, and embarrassment.
5. Don't build bad weapons.
Again, this is related to don't procrastinate and don't splurge. Taking workshops, using tutorials, and working in teams, will definitely help. Speaking from experience, building a weapon that will fall apart can and will injure someone (and make you look like an idiot).
If you want a cringe worthy laugh, you can check these out (trust me, they're no good): Cosplay.com (main) and Deviantart (contains some).