I'm going out fundraising tomorrow and I need tips!?

I'm doing two at the same time, actually, one that everyone in my grade gets and one from the school choir. Both are to reduce the amount our parents pay later for big trips. My best friend is coming over and helping out. I need some tips on organization and business sense. If I can get any opinions from people who regularly do fundraising (including selling Girl Scout cookies or something like that) that would be the best!