Forgiveness
When we are feeling upset or not at peace with any people (including ourselves), situation or event, we can use the following true forgiveness thought process examples.
On yourself
I am immortal spirit. This body is only an image It has nothing to do with what I am.
Source: Your Immortal Reality by Gary Renard, Pg 78On others
You are Spirit. Whole and Innocent. All is forgiven and released.
Source: Your Immortal Reality by Gary Renard, Pg 80A longer version
You're not really there. If I think you are guilty or the cause of the problem, and if I made you up, then the imagined guilt and fear must be in me. Since the separation from God never occurred, I forgive "both" of us for what we haven't really done. Now there is only innocence, and I join with the Holy Spirit in peace.
Source: Disappearance of the Universe by Gary Renard, Pg 256Yet another version
I must have decided wrongly, because I am not at peace. I made the decision myself, but I can also decide otherwise. I want to decide otherwise, because I want to be at peace. I do not feel guilty, because the Holy Spirit will undo all the    consequences of my wrong decision if I will let Him. I choose to let Him, by allowing Him to decide for God for me.
Source: A Course in Miracles (T-5. VII.6)Notes:
The you and you're can apply to any person, situation or event. It is all right to improvise while maintaining the basic ideas.
In addition, we could gently remind ourselves that "there is no world" and laugh it off.
In addition, we could gently remind ourselves that the person, situation or event is our own projection so that our unconscious guilt stays hidden and we could blame something outside ourselves. It also does not matter how bad or serious it appears to be, it all traces back to the unconscious guilt stemming from the illusory idea of separation from God.
Real forgiveness would see everything as being one and connected thus there is not really anyone else who is separate from you. Therefore, to forgive another is to forgive yourself.
Always be appropriate. Don't be weird and say it out to others. The forgiveness thought process is done in the mind.
It doesn't matter when we do it (there is no time). Even if we forget (and we should forgive ourselves for that), we will be provided with another opportunity eventually.