The best thing anyone with bad credit can do to improve their credit scores is focus on building positive payment history. In fact, payment history accounts for the largest percentage of your overall FICO score, about 35 percent, so its importance can't be ignored. Build recent positive payment history on your credit reports, and the old negative marks will have less of an impact on your scores. It's that simple. Unfortunately, if you have bad credit, there's a good chance you've had payment issues of some sort in the past. Late pays, charge offs, and collections on your credit reports are all ultimate credit score killers! But if you're reading this post, then I'll assume you're ready to put your past mistakes behind you and make a change for the better. And that process begins with making timely payments and building positive payment history as fast as possible.