A course of Feldenkrais Awareness Through Movement (ATM) audio lessons. Each can be studied on its own, or you can work your way through the whole collection to learn in-depth how to better sense and organize your body to reduce pain and improve your posture, balance, mobility, and power.
Lessons can be repeated as you wish, so follow your curiosity! If a lesson isn't comfortable initially, it's fine to skip it and come back to it later; you don't have to go through them in this order. When there's a close link between adjacent lessons, it's mentioned in the Context tab of the lesson notes.
Descriptions of each lesson give you a sense of its aim, though everyone's learning process is unique and you may find other benefits.
NOTE: Doing Feldenkrais lessons is the best way to improve your comfort and skill, but to learn more, check out Nick's teaching featured in these articles in Experience Life magazine.
After you complete the collection, returning to favorite lessons or progressing through from the beginning again will yield new insights. It can be very surprising to new Feldenkrais students how lessons you "know" are a different, valuable experience on subsequent explorations.