The OP is in high school.

IMHO, much of the advice given so far is bad. Fine for an adult with a steady job and good credit. Not for someone in their situation.

My advice would be: read up, educate yourself, learn what you can now. Don't jump in too soon. Get a job, slowly start working on establishing good credit before you go to try and exploit it.

Life is long and you have plenty of time. If you jump on a bunch of credit card applications now, you're probably going to only damage your credit and you'll then be starting off in the hole. There's no hurry, be patient (I know, try telling that to a 17 year old...).