What advice would you give yourself?

If you could write a letter to your ‘younger-self’ what (if any) advice would you give yourself?
Recently I have found myself wishing I could have done this. It makes me quite sad to feel this way, because I believe only sadness makes a person wish for situations like this to be possible.
I think I would tell myself that promises people make are a bad idea, and not to be taken too seriously, no matter what circumstances they are made under.
I would also tell myself not to blame myself for trusting, trust is a beautiful thing, and it isn’t my fault someone abused that .
What would you tell yourself?