1) Be a Cat or Mouse - Cute/Sexy black tight dress, thigh highs, heels, ears and boom you have the simplest best costume ever created. Best part is you don't look entirely like a jackass.
2) Wear All Black - Here is your chance, not like you need another one, to wear skin tight all black. Show off that body before winter comes and ruins it.
3) Camo - It's Easy - You can get it at a thrift shop, and easy to turn into a sexy costume.
4) Wear Heels - Every outfit, no matter what you are looks better with heels, this is a given
1) Be Miley Cyrus - Wear a bear backpack, DIY bear bodysuit, just stay away, if you want to dance slutty and twerk, fine, but don't do it in a Miley costume.
2) Dress as Food - No guy wants to go home with the girl dressed like pizza, burger or fries. Maybe you can pull off the cute M&Ms with a crew of friends but overall terrible costume idea.
3) Try to Hard - No one wants professional outfits, no one is impressed