When you're first starting to apply A Course in Miracle's idea of forgiveness, it begins with where you're at and what kind of a perception you have.
Most people will be starting out with a mind that is quite strongly convinced that everything external is real, that there are many very distinctly separate problems, that other people are very wrong and are the cause of all their problems.
With that way of perceiving, as you start learning to apply forgiveness it can be quite difficult. The idea that you've even been scapegoating at all is something of a revelation, or that blame is an attempt to project guilt, or that the person who is upset and accusing someone is actually the person who has the problem and not the person they're blaming.
Attempting to forgive when your mind is spending most of its time in that kind of a way of believing/looking at the world, seems like a big challenge and a big mess. It's hard to even remember the basics and harder still sometimes to get your mind out of the basic belief that you've been victimized by someone.
Taking back some sense of the projecting you've been doing at first appears to be the vast majority of what you "do" to forgive, because it at least is taking some steps to recognize that there may be more going on here than meets the eye. Appearances may not necessarily be true, and its possible there is another explanation for why it *seems* like someone else is guilty.
You can potentially spend some years just in that mode alone, learning each time you forgive that what you perceive happening has an explanation that's got something to do with you. That maybe you have some kind of perceptual or distorting problem going on in your mind which is changing how you see things. So then it seems that you go to town on your perception and learning to correct it.
After a while, because learning becomes generalized, and because correction of the mind becomes permanent, you gradually learn to form a clearer picture. You gradually peel away your conviction that problems are about other people. Each time each individual problem is forgiven, even if the forgiveness is not complete in its undoing (and early on it usually isn't), each example of you teaching yourself that there is a different way to look starts to turn into an overall different way of looking. It's like building a new way of perceiving one block at a time.
So eventually it's like, you've seen the same trick presented to you by the ego over and over again, and each time you've applied some kind of forgiveness, even if its a very sloppy inaccurate forgiveness riddled with mistakes, you gradually become clearer about what the truth is. And this gives you a firmer footing in the truth. You become less susceptible to being tricked by the *illusion* that there are many separate problems, or that the problems that show up are unlike each other.
Gradually it sinks in that "this" problem is actually pretty much the same scenario as "that" problem and you start to *transcend* the surface appearances. You at least begin to chisel away at the more obvious distractions and illusions, tending to fall mainly for the subtler ones or those that you didn't really tackle before. But you're still making progress and your mind is gradually learning to see *all* problems differently.
So with time, pretty soon you are not so easy to fool. You've seen the trick one too many times and have learned how it is not the truth. So it's kind of then like, you will notice the trick quicker and catch yourself and not fall into the trap so easily.
Also what happens over time then is you go "deeper" into your truth, which means your mind is waking up and you're examining and sorting out true from false at subtler or more abstract levels. Your refinement of "how" to forgive continues and you just keep collecting more and more insights. As you develop the right minded thought system and open up to Holy Spirit's truth, gradually it builds upon itself and lightbulbs go off more and more often. Things click together more and make more sense, and you get this sense that you are "getting it" with aha moments.
Some years later perhaps you might notice that you're no longer really fooled by the major surface appearances of problems and issues, but instead are operating at a much deeper level of forgiveness. What needs still to be undone are more fundamental beliefs, core values, major perceptual errors, profound beliefs about the basic nature of what is real or not real, etc.
When shit happens, most of it will not stick. The part that continues to stick continues to show you ways that you need to refine your grasp of the truth. But your forgiveness in general, the activity of what you need to do to correct your mind, dwells more often in the realm of what's going on within yourself. Having taken back a lot of your power and responsibility and owned up more to your part in what you experience, it becomes more a matter of just continually owning up to the truth rather than having to deal with lots of projections or blame or being heavily lost in stories and dramas.
It becomes more about what you are doing to yourself, what's happening in your own mind, recognizing that you've been inside your own private world and so have others, and also the growing awareness that intellectualizing the course does not lead to love. And yet, growing within you will also be an ever stronger sense that love, as simple as it sounds, is the key to everything. It is the truth that you want, it is the experience you want to have, it is what you want to share, and it becomes ever clear that simply love is the answer you've been homing in on this whole time.
It's all just a long process of refinement and clarification and chiseling away at beliefs in separation until your mind is returning to an awareness of wholeness and a truly forgiving attitude. Just being love.