step 1: HAVE A JOB. if you're going to be independent, be independent. Be able to pay your rent and your car and your bills.
step 2: MOVE OUT. Often it's easier to move in with a friend first time out - have someone to share responsibility (and get fucked up nightly) with.
step 3: DON'T MOVE BACK. A lot of people move out before they are ready and can't pay their bills, can't take care of themselves in the big bad scary world, and end up beggin their parents for money - or eventually move back home.
You need to create a new social network that has NOTHING to do with high school, your parents, or the town you grew up in.
That being said, I left at 17 for college and never looked back. It can be done. Even in today's irresponsible "tweenager" world of the "stay at home until you're 30" crowd.
