Insight!
Practice to become more “familiar” with the material, not to get “good” at it. Assume the getting good part, and focus on really “knowing” the material. Becoming aware if it, and, simply becoming very familiar with it. Intimately aware, like you are old, old friends, or hey, family. Hey! Familiar, family! Yup. There ya go.
The body with execute with ease if it is allowed to. Let it travel down well worn roads, in a favorite old pair of sneakers.
Focus is the challenge, especially if you been playing for years and years. You don’t realize how little your attention is really trained on the task at hand. You’ve gotten good enough to sale through a lot, fooling many, even most, including yourself.
You just want to be efficient and get “good” fast. After all, you’ve got a gig to do in 3 days or whatever. Focus. Become familiar. Good happens.