There are certain kinds of problems that don't allow you to overthink. If you are on a tight deadline and you need to get something done (e.g. fix a bug, add a feature) then the situation forces you to make _a_ decision and move on. You can only overthink when you don't have hard deadlines. So as an exercise, try to pick challenges that have deadlines (ideally external to you). It helps to work with other people, take up on some responsibility and commit to delivering.