You might consider exploring mindfulness meditation. I personally use Headspace, an app on my cellphone.

One of the best ways to clear your mind, in my experience, is to be in touch with your body. In this regard, I have found the writings of Jon Kabat Zinn and Thich Naht Hahn to be of great help.

Tony Stanton, MD

You might want to get into formal psychotherapy. Other options: Learn about mindfulness. Many self-help/self-development books about mindfulness and cognitive-behavioral therapy are out there. Talking about cognitive therapy, I highly recommend a self help book by Dr. W. Dyer: “Excuses Begone”