Trying to forgive other people is an error. It is not the kind of forgiveness that ACIM teaches at all. It is an attack.
First and foremost, when you are in a state of unforgiveness yourself, you are perceiving incorrectly.
This erroneous perception is a state of judgement. This judgement causes you to mis-perceive. Your mis-perceptions show you things which seem to be real or true, which are not.
So as a primary starting point of all "forgiveness attempts", you pretty much will always find yourself believing that someone else is the problem.
Perceiving that someone else is the problem, the ego will step in and will guide you to take action. The action recommendation will be, "you need to forgive them."
THIS IS A LIE!
As soon as you begin to attempt to do something in response to the FALSE PERCEPTION that the other person is the one who needs to be forgiven, you will fall into the ego's trap even further. Attempting to forgive them is an ADDITIONAL LAYER OF LIES on top of the false perception you were having to begin with.
What then can come across as a desire to be more forgiving, as though more spiritual, is in fact an additional layer of attack. Those who are trying to forgive others for what they seem to have done, are attacking them, all in the pretense that they are being more holy, spiritual or forgiving, when in fact it is another form of condemnation in disguise. You've gone from bad to worse.
The "trick" to correct forgiveness is not in the REACTION to what you have mis-perceived, which compels you to think you have to forgive the fucker who just did something that upset you. The trick is, that you need to realize, that the only reason you THINK that the person is the cause of your upset, is because of YOUR FALSE PERCEPTION, and therefore something is wrong with your perceptual mechanism.
Your own perceptions are mistaken, and it is causing you to see other people as sinful when they are not. It is causing you to believe and perceive that they are causing YOU, producing effects in you, and that you have been victimized.
YOU HAVE NOT.
The "problem" you are trying to deal with or heal is NOT THE PROBLEM. The problem is not what someone caused or what someone appeared to do. The problem is that YOU are not seeing correctly. YOU NEED FORGIVENESS AND HEALING, not them.
Other people have absolutely NOTHING TO DO WITH your upset.
Therefore, to correctly forgive, BEWARE of the temptation to think that you should "forgive them". That's a trap. It's a mistake on top of a mistake. You do not need to forgive them. You need to STOP, question whether what you perceive is EVEN REAL in the first place, and then set about the proper correction of YOUR broken perception, via YOUR mistaken beliefs, which are beliefs about YOURSELF, which need to be recognized as FALSE.
It's YOU who needs forgiveness, not anyone else. You CANNOT FORGIVE ANOTHER PERSON, because no-one else has really done anything and no-one is the cause of you. You are the one with the split mind, you are the one with ego judgement distorting your perceptions, you are the one who sees yourself as unfairly treated, you are the one who needs forgiveness OF YOURSELF, because of what YOU DID NOT DO.
You think you sinned, and you have tried to put your sin onto others and see it there, then attack it, to make out that it is not your problem. You are the one who needs correction. You can only forgive yourself. All attack is self attack.
The truth is, YOU DID NOT SIN EITHER, and sin has not happened at all, and there is no truth to sin, and sin is not real. Therefore, YOU are forgiven, and therefore in recognition of this you will accept that YOU are innocent, and then you will stop blaming your stuff on other people, in an attempt to then forgive them for what you think THEY did. They are not the one holding onto sin, it's you. YOU need forgiveness.
And you are forgiven, because you have not sinned, you cannot sin, you are immortal holy innocent and whole and free, are incapable of real sin, real sin does not exist, you have not separated from God, and therefore nothing has happened. Yay.