In Traditional Chinese Medicine, the fall is associated with Metal element and corresponding to such organs as Lung and Large Intestine.
As nature moves from an expansive and active summer life to contractive and internal autumn existence, our life should slow down and focus on the inner self more. It's a great time to start projects that focus more on the internal and retrospective parts of life and finish up your spring projects.
That's, why it is good practice to organize and let go of the old and make room for the new things in your life. Organize, clean out, donate - these practices will help to "let go", liberate yourself and live in harmony with the season.