See all 5 points, but no. 1 is the most important to begin with.
1. Pray for a deeper conviction of your own sin.
I want to encourage you to ask God to show you as never before the depth and misery of your own sin.
James 3:13-18 to 4:1-6
Meditate on the roots of my own sin; see it for how gross it is; and then look to Christ and see His forgiveness of my own sin; and be amazed that He forgave me, therefore I can forgive others and be free from bitterness and overwhelming patterns of anger.
No. 3 – pray for the wisdom from above (James 1:5) and then the description of true wisdom – it demonstrates it’s fruits by “the gentleness of wisdom” and “good behavior” and lack of bitterness and selfish ambition. see and meditate on James 3:13-18; and 4:1-6
Why can’t I overcome my bitterness and anger?
Most of our bitterness and anger towards others is rooted in an inability to be profoundly amazed at Christ’s love for us in our sin. If you are struggling with bitterness then it may be that the Lord is letting the very sin that is flowing from your inability to see Christ be the means by which you come to see him.
That’s what I would pray. “Forgive one another, as God in Christ forgave you” is an unbelievably important word in Ephesians 4:32. You now have the potential of feeling forgiven by God for things that are mortally dangerous, which might open the door for greater grace towards this other person.
Pastor John Piper