Two particular points that have helped me get better is 1) don't ignore your inner voice when it tells you are have done/are about to do something wrong and 2) keep logs of your tasks through the day. Add recurring tasks to check lists. Automate away dumb work, leaving more time for learning.
RE 1) a lot of my mistakes are the result of/been made worse by ignoring that feeling that things aren't quite right... e.g. an error message in a log that doesn't seem to have had any effect and you have seen before, but you don't quite understand. Don't leave that lie, add it to a TODO, understand it and fix it.
RE 2) grind away problems with first logging your recurring work, then automating away as much work as possible. It can be a complicated script or it can be simply a link in a checklist, anything to save you time. Make sure to make your manager aware of this work, it can go unnoticed otherwise.