high school sucks. people are dicks (not just the students), teenagers are chock-full of hormones, the work is pointless and stupid (i remember learning the word 'triangle' in tenth-grade study skills), and four years is a long time (especially when you've only lived for about 14). it's generally an exercise in making people miserable, and it works very well.
don't be a dick I: don't insult others because you're shy, don't insult to tease (this is a million times more true if they're not teasing back), don't insult their music, don't insult their sports, don't insult their religion, don't insult their politics.
don't be unnaturally shy: if you want friends, let people do things like copy your homework. no, they're not really your friends if that's all they like you for. so copy from them, too, if they're around your level.
don't try to fit in. if you don't already, you never will, and nobody likes a poser. be yourself (but not a dick).
don't be a dick II: if somebody brings up a topic that's important to them (hockey or religion, for example), don't say something along the lines of 'gay' and end the conversation.