Admit it when you are wrong.

I might not always do this, but I try to always admit it when I have made a mistake. When you admit you are wrong you gain credibility as an honest person.  When the person knows that they have caught you in either a lie or a mistake, and you refuse to admit it, they will have trouble ever trusting you again. Lies, blame shifting and avoiding the truth will only get you so far before you get busted.