The most basic skill is prioritizing. When you can effectively decide what is more important that something else, you can decide what needs to be kept. If it's important, you will more easily decide where it should go.
Basic organizational skills are being able to keep your belongings in a neat and orderly fashion, and keep track of your time efficiently. You can hire an organizer to help you out.
List first the things you want to do then put then on a time schedule. In that case you will know the things you have to do even if you can't follow your time schedule at least there are listed things you still need to finish.