Tips & techniques for dealing with bad memories?

Any recommended tips & techniques for dealing with bad memories you'd rather forget?

I'm in my early 40s and about 7 years ago I confronted my NMom & NStepdad. We're limited contact now & I am a lot more content. However, I still go through the process of 'grieving' for the life I didn't have. I realize I probably spent 30+ years of my life with high-functioning depression. I do have some good memories, but with an undercurrent of sadness. There are large periods of my life I'd rather forget. Lately, I've tried to be mindful and redirect my thoughts if I start to think about the past. Any other tips anyone uses? Thank you.