 With a personal finance minute, here's Greg McBride. Don't believe these myths about how to improve your credit. Credit building is filled with bogus advice, so don't be too quick to believe what you've heard. For example, you may think that closing old accounts will boost your credit score. No, this is a move that could ding your credit because you'll be left with a smaller amount of available credit and it will look like you're using more of it.