Sarcastic Gamer writes:
"Step 1 - Keep it short
No one likes a long username - they're hard to remember, take a long time to type in and are often hard to read. I'm not suggesting that you have a username that's shorter than 4 characters, but for usernames, shorter is always better. I would say 10 characters is an absolute maximum, but 6 or 7 is where you should be aiming for. If you can think of something shorter, then go with that.
Step 2 - Make it abstract
A common mistake people make when picking a username is trying to name it after someone or something else. I don't care if you're Just Cause's biggest fan..."