Did you go to the freshman preview weekend?
Do you know people in a frat already?
What i'd suggest if you have a buddy, to go to USC for a night/weekend this summer to scope out the scene. Say you're coming in the Fall, but wanted to come and chill for a night and party or whatever.
Keep in mind, the "good" fraternities at your school may already have their pledge classes locked up before rush even starts. Many fraternities do indeed do "dirty" rushing, meaning they pinpoint their pledges during summer parties. Of course, this may not be the case for your semester or even your school.
I want to note that “pinpointing their pledges during summer parties” is not considered "dirty" rushing by the NIC and the majority of campus IFCs.