If you've already accepted and put in a deposit, there might not be much you can do for this year other than take out some loans. I would continue looking for scholarships both at the local and national level. Are you going away to college or going somewhere near home? If you're going away, you may want to consider becoming an RA next year. It's a tough job, but you'll get free room and board usually. If you're going somewhere nearby and living at home is an option, I would strongly consider that. You may also want to look into programs like AmeriCorps. You'd have to take a break from classes for 10 months to a year, but you will get money to put toward your education.
Best of luck to you!