It is no end of fun to create characters. You can create a character based on someone you like/don't like, powers you wish you had, or even an appliance in your kitchen.
This handy sheet walks you through some basic questions to get character-creation started.
It's based on my classes, as well as field trips I help with at 826 Valencia (check them out, support them) - and it's designed to help you begin to picture your character clearly in your mind.
You can answer all the questions, or just a few - but as soon as you start, your character will begin to seem more real. Then you can loose him/her/it on the world!