if you really want to start a business plan to work your ass off.
figure out what you wanna do, is it service based or sales based?
go get a business license, file the shit for a corporation (LLC's are much better for both the business and the owner).
my family's always owned businesses, i owned a small lawn care company when i was 16-17, still have it just havent worked hard at it this year (moving for college)