This is a difficult one because every case is different. Since already people tell you "the regular things" pack, I'll tell you a different thing you can try:
Every morning 20 minutes: Sit in meditation position, concentrate on relaxing your body, in having a calm and steady breathing at first, and when you are calm and relax, imagine that you are drawing, try to feel it real, try to feel the strokes of the pen in the paper, imagine you are doing a fantastic work and you are very happy, try to visualize things, try to see things, faces, bodies, scenes, the more clearly possible in your mind, now try to imagine your personal world, the things in the way you see them. And last, imagine that you already did a fantastic work and do concentrate on the feeling of satisfaction, try to "be" that feeling, let it flow through you. Enjoy it.
I just started trying these techniques and in my experience, they work, but not instantly, is like a learning, but I really notice improvements in all areal. This is no new, athletes use in your training for example.
Well, have a nice day and don't stop making great pieces!!!!