get a department store credit card, use it at the checkout, then pay in cash immediately. Your credit score will go up with every purchase. Obviously, don't leave anything on credit card since its a ridiculous interest. (29% at some places)
If you add another, you can do the same. Your credit rating will rise very quickly.
Bonus, if you find a store with points of some kind, you will be paying cash in reality, but bumping up your points.