Try to find a username that incorporates some kind of pun or wordplay. If you can create wordplay based on your name, you'll end up with a username that is clever, funny and reflects your real identity.
If you don't want your username to include or reference your real name, think about interests you have or personal quirks you have. The quirkier your username, the cooler it will be. What's your favorite silly poem, sport, animal, or book? Consider an emotion that you often identify with, or an adjective you enjoy. Why not reference those options in your username? Instead of just using your name as the basis for your username, you could combine various words or numbers to come up with a username that still relates to who you are.