Make lots of to-do lists. Make them on your phone, on pieces of paper, at the front of the book you are reading. Not just for the groceries. But what you want to achieve, what you might watch, listen to, read. Things someone said to you that you ought to mull. Things you want to say to someone. You'll start to think in a more ordered way. Make them when days are ending, and weeks are starting. Make them at the coffee shop when you don't feel like doing anything else. The lists will begin to lodge in your brain so that you don't have to consult them. You'll be better at getting done what you need to get done and more than that, too. The "more than that, too" part is crucial.