Don't hold onto anger. Don't blame others for your mistakes. Apologize for your mistake, learn from it. From that point on, it's really out of your hands.
Not a revenge-oriented person, but really. No need to even avenge ourselves. (1) God is our avenger (2) Bitterness is poison (3) Some people just don’t deserve that place in your life. Hate and bitterness take too much energy that could be put.