what is the best thing to do with old regrets?

we hear a lot of advises on how to pick ourselves up after going through some disappointments. 'learn from your mistakes', 'forgive and forget', 'life goes on anyway, so make the best out of it' and many more. but all these are so true. we might have heard them spoken time and again, but always, there will be a ring of truth in them. forgive then forget the hurt for life goes on, avoid doing the same mistakes as we have already learned from our past experiences.