Don't say your having a party till the last minute. If you start telling people now then your gunna have way too many people you don't like showing up. If you wait till the last minute to tell people then the people you want will show up (whose gunna miss a night of partying) and only a reasonable amount of random people will show up. Trust me, I've been through high school, even the biggest parties get blown up when its been going around for a week before. Depends on your high school and where you live though.
Ask everyone whose drinking for $5, get 30s and handles of cheap vodka, ask some girls to bring mixers or buy some yourself.
Try getting people to dance. For some reason no one ever had dancing at parties at my high school. Download some party techno mix and play it over some speakers, have the lights turned off, you can even get a small strobe light from spencers gifts for pretty cheap.
Everyone has a better time and are willing to get more wild drunk when its dark and there is dancing.
Themes can be hard to pull off because people don't really have that much time to get shit together and can be sketched about seriously dressing up so pick something easy but fun. One of the best nights I ever had was when my friend threw a 'jersey night' party which was everyone wore a basketball jersey/lax pinnie/etc even the girls and it was just wild.