There are a few main groups of people
Preps: Normally all look the same, large majority of the school. Abercrombie and Hollister wearing little pricks who find anyone or anything different "creepy" but still consider them selves quirky and creative for wearing 3D glasses with the lenses popped out.
Scene/Emo: All like the same bands I,e 3oh!3, muse, asking Alexandra, BIG bring me the horizon fans. All look the same and tend to dye their hair to seem "different".
Cocky Jocks: Not liked by anyone but the preps and tend to have relationships with them that last about a week. Wear basketball shorts everywhere and consider each other "brothers" but still call people fags and homos. AWFUL to have gym with.
Nerds: Hang out in small clusters with other nerds. Talk about Minecraft 60% of the time and have mass nerdy sessions where they try to "out nerd" each other by knowing more about any given sci fi books/shows. 75% of them are potheads and thought of as "bad influences" by the preps.
Ghetto: Also have short relationships. Wear lots of leather and colorful skinnies, talk in so much slang sometimes you cant even hear what they're saying. Either nasty-skinny or total fatass.
Genuinely Strange People: Breathe heavy most of the time, wear bargain basement clothes and never wash their hair. Try to talk to nerds but are shunned for their lack of brains. Some church freaks who yell about creationism in science class, very scary people.