Use only the first one or two syllables of your given name. The most common kind of nickname is just a truncated version of that person's first name. This is pretty basic, and can be a good option if you're changing schools, going off to college, or starting a new job, and you want a fresh start. It will be easier for you to adjust to a nickname that sounds similar to what you're used to being called, and because you will be meeting new people you won't have to ask them to start calling you something different than what they're used to.
