The very first step in forgiving someone who's sinned against you is to seek God's forgiveness for your own sin of not forgiving them. To not immediately forgive someone is a sin and only when we confess and forsake the sin of unforgiveness can we then begin to walk on the path of forgiveness ourselves. More
One of the most difficult things one can do is to ...forgive! It's not an easy task to forgive someone who's offended you and/or hurt you, yet you and I are called by God to forgive others. In fact, the Lord's prayer includes forgiving others (Matthew 6:12).