1. Read sacred texts with care. Take notes. 
2. Acknowledge human authorship of said texts in historical context
3. Separate and discard practices and behaviour reliant on belief in omniscience, omnipotence or omnipresence. 
4. Separate and discard practices and behaviour which denigrate any group of people as “less than,” or “unclean” on the basis of any criteria. Criteria may includes, but are not limited to: age, sex, gender, sexual orientation, body shape, skin pigmentation, native language, hair colour, hair length, tattoos or lack thereof… No, really… anything.
5. Separate and discard practices and behaviour based on lack of refrigeration, understanding of biology, proper hygiene, and or physics (see point 2)
6. Separate and discard practices and behaviour reliant on higher authority. This includes reliance on gurus, Imams, Priests, monks, and or keepers of the sacred colander.
7. Ask self: “Self, does this teaching make me want or try to be better person without hurting anyone?”
8. Season with salt and pepper
9. Serve warm

“I am myself indifferent honest, but yet I could accuse me of such things that it were better my mother had not borne me.”
—Hamlet, Act III, Scene I

“So in everything, do to others what you would have them do to you, for this sums up the Law and the Prophets.”
—Matthew 7:12, New International Version

Full disclosure, I am a post fundamentalist Christian. I claim to be an atheist, but I am steeped in the teachings of fundamentalist, Protestant, evangelical Christianity. Having said that, I think that religious teachings can contain a lot of wisdom. The first question to be asked when discussing forgiveness is, “Who needs forgiveness?” I think one of the reasons that Christianity has had such staying power is that it understands that we all need forgiveness, and religious leaders of all stripes, unfortunately, have preyed on this, throughout human history.

There is also a lot of wisdom in the Golden Rule. “Do to others as you would have them do to you.” The kernel of truth in the Golden Rule isn’t simply that it is a good idea to treat others the way you want to be treated, it’s often impossible to deal positively with others in any way, unless we have first done so for ourselves. If I want to become a forgiving person, the first person I must learn to forgive, is myself.

The first requirement for this process is empathy. If one has no empathy, then none of what I am saying here will make any sense, but if one has empathy, very often the person who is most damaged by a destructive act, is the perpetrator. People who commit evil acts rarely sleep well, and that isn’t just a cliche, or a tale told to scare children into behaving.

Religion provides an easy answer for this. The ultimate victim of every evil act is the assigned deity. So all you need to do is get that deity to forgive you, and you are golden. When I understood that that was a lie, suddenly the entire process of forgiveness became more difficult, and ultimately, more meaningful.