Don't use a video game title in your name, don't use numbers, don't make something obscene like "poopkid123", don't use copious amounts of X's or L's or V's to try get the name you want ("xXDeathReaperXx", lKiLLeRlFail", "v Butteckz". Don't alternate between uppercase and lowercase (KiNgOfCaLlOfDuTy).
Avoid these things and you wont look like a dumb faggot.