In most scoring models, payment history and credit utilization (how much credit you use) carry the most weight, followed by the age of your credit accounts, new credit activity, and your mix of credit types. If you're building credit from scratch (like I did) or rebuilding credit after making some mistakes with credit cards before, a secured credit card can come in handy. Credit reporting: Not all credit cards report to all three credit bureaus, which can limit their effectiveness in building your credit.