Unfortunately there are no easy ways or quick fixes to deal with bullies. But from my experience this is the advice I offer.
1. Telling a teacher or principle is only going to worsen the situation. It's going to make the bully KNOW that you are afraid of him or her and will the propagate more bullying regardless of threats or punishments.
2. A bully's power comes from fear and hurt. The simple solution (for me) was not to be afraid and to at least pretend not to be hurt by their words. This is not easy for most people. But it can grow with confidence, which brings me to my last point.
3. The ability to defend yourself is one that cannot be replaced with anything else. Being confidant that you can handle yourself in a physical altercation will make it possible to to shrug off the hurtful words of others. I have four daughters (3 of which were enrolled in public school, we are now homeschooling since we've seen the vast deficiencies in our public school system) And all three of them are taught self defense on a regular basis (by me as I have been trained to be law enforcement, though we have rented a few videos that focus specifically on girls and on children) And with enough practice I saw their confidence grow and reports of bullying all but stopped.