Actually it's not, but what you look like when you're performing does play a big role! Here's just some advice! (:
  1.  Dress the part. Don't dress like a prep if you're playing metalcore music. And don't wear all black and chains if you're playing an all acoustic set. 
  2. It's okay for guys to wear makeup! If you're a guy, and you really wanna wear makeup, don't be embarrassed! Nobody will make fun of you. A lot of famous male musicians proudly sport the guyliner, from Adam Lambert to Marilyn Manson to most of the emo/screamo people.
  3. Your appearance should reflect your onstage persona. Need I say more?
  4. I offer band stylist/image consulting services! Hit me up if you have any questions!