• Don't even think of going car shopping without knowing your credit score. You can get a free credit report here.
• If you keep getting turned down, stop applying immediately because each rejection lowers your score. Find out your credit issues and work on them.
• Know you're going to pay more for a bad credit auto loan but don't freak out about it. Consider it a bad credit tax. On an $8,000, three-year loan, the difference between a great rate and a subprime rate works out to just $1.14 per day -- and you can blow that on coffee.
• Don't overspend. Here's a link for a handy car loan monthly payment calculator. Figure out the price of the car first, and use the calculators to make sure you can swing the payments.