Walk in to the bank, talk to a loan person, and tell them that you want to borrow $500, (or whatever the minimum is), and you want to back the loan with cash. (the cash that you are borrowing) They will lock it in a 12 month CD, and you'll get a payment book. The first 7 payments, you make each week, using a coupon from the payment book. Then Make the remainder of the payments on time each month. You will have made 12 payments in 6 months, and paid it off.
You now have some credit with that bank. And it's been reported.
Just to add to it, borrow double the first amount, and back it with cash. (you can actually cash out on this one) and make payments same way. You will have established a good line of credit with the bank, and will be able to borrow a significant sum from them with just your signature to back it up. Even more if you want to give them a mortgage.
At least that's how I did it. YMMV