The fastest and most effective way to raise your score is the 2 following things;
Reduce Debt. maxed out credit cards will hurt you. Pay down cards to 35% or less.
Remove Negative Items . This means getting rid of 'bad marks' on your credit report by disputing them with the credit bureau. You can do this yourself or use a credit restoration service.
A secure loan (mortgage/car loan) is actually the best type of loan for building your credit history. These types of loans are almost always reported to at least one credit bureau (Lexington Law Firm has a free consultation number: 800-223-7615)
I would advise you to stay clear of a sub-prime merchandise account. These are typically high interest/high fees and have tricky terms.
Good Luck