If you had a bad relationship with somebody it is best to follow these steps:
Usually there are faults on both sides in any relationship problem. One of the keys to being blessed by God in this area is humility. You may consider that the other person is 90% to blame, while your blame is only 10%. Nevertheless, you are not responsible for that person’s attitudes and actions, only your own. There is the possibility you have misunderstood what they said and did. The more you humble yourself in this process the more you can expect God’s blessing.
a. Ask the Holy Spirit to help you and lead you to a proper resolution of the problem.
b. The key to your emotional healing is forgiveness. Tell God that you forgive that person, whether they change or not. (Luke 23:34; Matthew 6:14,15; Mark 11:25; Matthew 18:35; Colossians 3:13). Keep on forgiving them as often as is necessary.
c. Ask God to show you where you needed to behave or respond differently in the relationship. Ask God to show you where your attitude is or was wrong.
d. Contact that person – ideally in person, but if time does not permit, by phone and/or by letter. If you have lost touch and still don’t feel right about things, ask someone who might know the contact details of that person. Follow through diligently. (Matthew 5:23, 24).
e. Tell them that you are sorry for the way you acted in the relationship. Confess to them all the things you believe were not right on your part. Ask for forgiveness.
f. If you stole things from them, ask them what they would like from you as far as restoring those things and do what you can in the future to pay them what you owe them.
g. Give them an opportunity to confess their faults. If they don’t, try to explain how their words and actions made you feel, and the way it seemed to you.
h. If they apologize, express your forgiveness to them. If they don’t apologize, then be gracious towards them and express the fact that you are sorry that there cannot be more reconciliation at that time.
i. If hurt still comes up in your mind after the meeting, pray for them and bless them. Ask that God will get through to them with His love and that they will be set free from all evil. Keep choosing a decision and attitude of forgiveness.
j. If they are a believer, or especially if they are a church member with you, follow the steps mentioned in Matthew 18:15-18. Do not bypass any of these steps, or you yourself will enter into sin and get into unrighteous judgment.
You have to be led by the Spirit in these matters. If your sin has not hurt that person, it is best not to say anything. For example, don’t go to someone who trusts you and say, “I just want to confess to you that I have been having all these evil thoughts about you.”
This list does covers the basics but is by no means exhaustive. There are good books on the subject, but the best book to read is the Bible. Look at the example of Jesus and remember that the blood of Jesus is enough to cleanse your sins.