I can only speak about forgiving my perpetrators from my own view of life. I'm a serious Christian and I try to obey what the Bible teaches me. Jesus taught what we call "The Lord's Prayer" and that includes a plea for God to forgive us, "As we forgive." (See Matthew 6:19-13.)
Many people don't go on to read the next verse: "If you forgive those who sin against you, your heavenly Father will forgive you. But if you refuse to forgive others, your Father will not forgive your sins" (verses 14–15 NLT).
The process begins with my sense of being forgiven, just as in the Lord's Prayer we ask God to do that. The next step is that we forgive others. Here's how I see it: The more I appreciate unearned forgiveness by God—and I call that grace—the more I am able to focus on others who haven't earned the right to have their sins taken away. The proof of my being forgiven is that I can then forgive.
It doesn't have to happen immediately and it may take weeks or months (as it did with me), but if we grasp even a glimmer of the grace given to us, we're ready to offer it to others.
This may not work for everyone, but it has worked for me.
Perhaps one of you would like to share your process of forgiving.
Or share your struggle that prevents your forgiving.