Before posting it make sure you have 3-6 members.
You need to have a good name. Something like GADFROD sucks because it is too long and weird
Try if you can to make your clan an acronym (When you get the first letters of each word in one name and it stay pronounceable, Eg, Cat (Can and tin))
Don't be like "OMG MY CLAN RAWKS AND URS SUCKS"
Don't focus it on death matches alone. Building is key to a clan.