From my perspective:
1. Get your credit score information
2. Consolidate your credit cards, get rid of others by cancelling them. Cutting the cards doesn't do it. CANCEL them by contacting the credit card company and officiallycancelling the account.
3. Pay your bills on time --- for credit cards, pay more than the minimum otherwis, you'll never get ahead
4, Don't apply for new credit accounts (from department stores, etc.. just to get a discount at your initial purchase)
5. Curb your spending
6. Establish good habits, and live within your means, i.e., you make more money than you spend.