Some research found that the what we regret the most are mistakes of omission not of commission.
Every time you feel you have made a mistake of omission, write it in a diary. It will give you a perspective of your mistakes and help you avoid them in the future.
To record your decisions and learn from them.
Keep a journal of every decision(that might have a long lasting effect) you make. Write down the alternatives, which one you chose and why. Much later (months or years) go back and see which decisions were good ones, and which had no real significance in the long run.
Track and see all your successes. Not just the big ones, but the small everyday ones – anything you deem a success, maybe your overcame an obstacle, finished an important task, etc.
An app that allows you to input any success and will store it with a time stamp, so you can see all of them in any resolution you want (day, week, month, etc.) You can also create a separate calendar in your current app where you input all of your these as a simple solution until such an app exists.