>>7 has a point, a good way to stop hating people or having negative feelings of any kind is to be a "smart ass" or a "troll". People will automatically ignore you if they know you're just going to insult them, or belittle them. That way you can be happy. Though the problem here, and the problem I found when I was in High School, is at the end of the day you don't know how to do anything else, you don't have many people who will hang around you and your self-confidence will usually be dependent on your putting others down.
A more mature and easier way i've found is just being tolerant and patient with people. This is more difficult to begin with, but you just have to think, why are they being this way? They must have problems of their own or something similar. People are rarely cruel or annoying for the sake of it, even it's simply to get a reaction there is always a reason. So first of all, deny them that reaction, if they continue to be annoying or spiteful do what you can to get them in trouble wherever possible, remain respectful and sensible but make their life harder when they are around you. Sooner or later they'll associate this with you and leave you alone. If they escalate to physical violence there's not much you can do. Don't attack them, but protect yourself if you can, defending yourself is a lot easier when you're only focussed on actual defence and again try and get them punished for this. It's very rare that anyone won't see that bothering you simply isn't worth it.
Otherwise, if you can't beat 'em, join 'em. You'd be surprised how easy it is to turn their attention to someone else, find out what they dislike and point that out to them. Though this is an absolutely despicable way to go about things, if you simply need to cope and know you can't deal with it this may be the only way. If you know you'd feel a little to guilty try sway their attention to someone you know can deal with it.
Finally just practice being invisible, avoid these people at all costs, be smart about where you go and who you talk to, stop talking to these people all together, it's obvious they all have self-esteem issues and are trying to find a way to "boost" their ego and self-confidence.. It just means they have very little in the way of intelligence and maturity. My solution back in High School was simply to cut contact with people like this all together. When they called out to me i'd simply offer a wave and walk away. If they kept annoying me i'd just go and hang around with another group of people. Lying constantly will probably help you here. It gives them less information and you can make up whatever you like, when people question you about it simply say something like "Haha, no, who's stupid enough to believe that?" Turn the rumours on their heads. It honestly sounds like it's not worth getting worked up over.
Just remember, and I know it's little consolation, but School doesn't last forever, eventually mature and intelligent people outweigh the "jerks" and what have you. Just be patient and try and focus on the good, or become a sociopath, being detached from your emotions means it won't affect you anyway. Though i'm not sure it's actually possible to "turn off" your emotions~