My reputation at school is horrible and i have no friends. what are simple things to change that?

U have my sympathy: Many of us grow up in environments in which we learn, or are forced to learn, behaviors that serve us poorly in the outside world. Others will not tell us how to change. Talk about the other person's interests & try to find what you can admire. Be good at something difficult & modest about it. For now, say only nice things. Don't discuss politics or faith. Deflect anger with a joke. Good luck.

Sorry, not simple: You haven't said how old you are, but i'm betting high school age. It's hard to transform yourself, but it can be done. The first step may be to consider picking out a person you admire who may not be the most popular but judges people on what's inside. Then get to work on not trying to be someone you're not. With summer almost here, by next september you may have most of your job done.