I haven't seen this one mentioned yet, though that may just be lack of reading carefully. If it has been, apologies. If not, *thumbs up* for me!
Get to know your professors. Not only can schmoozing help your grade (some professors will bump up your grade if they detect a genuine interest in learning from you), but getting to know your professors on a personal level can help you in the future. They can write letters of recommendations, make phone calls, etc.
I've only been in college for a year and a half (going back in the fall!), but I got to be friends with a professor in my department. When I left school she got me my first interpreting job without even going in for an interview, but she's helped me look for other jobs as well. Plus, she used to pay me to help her come up with presentations for her class, and to do research with her.