Think of your name in your head. Lets say it's Isabella. Isabella is quite a popular name at the moment. If you want a shy nickname, try going with Bella or Belle. If you want a name to show off your spunk, you can try Izzy. Test the name out in your head. Say like "Hi, I'm..." Or "Cool!! I'm..." If you don't like how it sounds, change it!!! Make sure its not too outrageous that you feel embarrassed introducing yourself, or it will never catch on. Try it on close friends. Send a text or phone them or go visit their houses and ask them, not too desperately, but along the lines of "Hey! What you up to? Hey, please can you call me ____ from now on? It just sounds cool, that's all." If they refuse, don't worry about it. Perhaps they need time! Introduce it to fellow classmates and family, not with too much pressure though. If this is successful, your on the track to success. If not, you probably have known them for too long, but don't be put down! Keep on trying! Start signing informal letters and forms, perhaps even schoolbooks with your nickname. That will show everybody that you are serious.