Dr. Schuller provides this advice on forgiving another person (excerpt):
I submit that FORGIVENESS, as a human value, is the most powerful healing force there is. Some of you are carrying a grudge against someone, and you need to forgive. Some of you may need to forgive yourself. And that is the only way you will find healing for your sorrow, the removal of jealousy, or the erasure of bitter memories. Where in your life do you need the miraculous power of forgiveness? In a few words, identify the area of your life where you need to experience forgiveness:
Now, in your mind imagine that you are approaching the one whom you need to forgive. You explain the feelings you have had and the need you now have to be forgiving. In love, you ask forgiveness for not having been forgiving of them. Then imagine that you experience the warmth of reconciliation. Enjoy that feeling, and then begin plans to work out the above scene in real life.