Another word for forgiveness is "honesty". It's to do with admitting to the truth and being clear about what the truth is. This entails surrendering of the ego's motivations and lies and owning up to responsibility and authenticity. But it's also an honesty that goes beyond appearances, physical events, what it looks like happened or who seemed to be the cause. Because, in all honesty, such "truth" is not the truth.
If you are in the middle of some ego tangle, upset emotions flying all over the place, believing that it's caused by someone or something other than yourself, then you're not really being honest. To be honest you'll have to really take a good look at what you're doing any why, and if you can discern and see what it is you're doing, you will have to admit to yourself that you've been deceiving yourself.
A big part of the problem of how to forgive, is that when you're in the middle of a dramatic story you're really quite lost. You've lost track of clarity. You've lost sight of what the truth is. You're deluded and distracted by something big and ominous which *seems* to be the problem but really isn't.
You've pinned the blame or cause for this story onto something that isn't the cause of it. You generally aren't seeing clearly. There's so much going on and so many things which seem to mean something, that it's just all very confusing. This confusion essentially is dishonesty because you've lost touch with the truth and are defending evidence of that which is false.
So really, if you have no other practice, it would be useful to remind yourself from time to time, that you need to get HONEST as quickly as you can. And this honesty involves questioning what you've been doing, how you've been perceiving, what you've been believing, and all the "truth" that you made up that hasn't come from God.
Honesty shines a light to help you see clearly and puts everything into its proper place. It's admitting to what's really happening, admitting to how you feel, admitting to what you're experiencing and admitting to what's really causing it.
When you're upset and its because someone else did something or didn't do something correctly, it's because you've disowned responsibility and are projecting guilt, which is a dishonest act. It's not the other person's guilt or sin. You're passing your sin off onto them and believing they're the cause of it. This is dishonest. It's deceptive.
The person who stands to gain from your honesty is yourself. Owning up to the truth sets you free, aligns your mind to the truth, clarifies what is happening in the situation and helps you to see correctly. When you can see correctly and clearly you get back in touch with the experience that, in truth, you are perfectly happy and at peace and free of all ego suffering.
Honesty is not good for the ego. It's not good for the part of you that wants to keep a story going. It's not good for the part that wants to control and blame and manipulate. It's not good for maintaining a cover or keeping up appearances or putting on a face/persona. It's means revealing what is real, and that means there can be no cover-up.
Where are you being dishonest with yourself, what do you need to own up to and admit to, and are you willing to surrender your support for maintaining lies that are only bringing you suffering?