Once you've decided to seek out scholarship money to pay for college, the first person you should talk to is your high school guidance counselor. Part of the job of a guidance counselor is to know what's going on with regard to grants, scholarships, and student loans; so he or she should have some information about everything from the national aid programs to the local scholarships that may only be available to students from your school or town. If you attend a large high school with a staff of counselors, it could be that one of them is the "scholarship specialist," so don't be afraid to ask.
Also, remember the golden rule about seeking out financial aid: leave no stone unturned. As you search everywhere you can think of for information about scholarships and financial aid, don't forget about friends who attend other schools. Share with them what you learn about scholarships in exchange for information they heard from their counselors, and you may both learn something valuable.
Don't assume that your counselor is the only person in the whole school who might know something about financial aid. Your teachers were all students once, too. Spend some time talking to your teachers about the colleges they attended and ask them if they know anything about getting scholarships. Even if your teachers have no specific advice, they'll make good references when you decide to pursue a scholarship or grant.