Skills building never stops for ambitious, hard-working basketball players who are constantly looking for a way to improve, or perform at the highest level. Just watch Steph Curry or Diana Taurasi warm-up, and you will recognize the same drills you do at the youth level: two ball drills, progression shooting, working on your footwork, perfecting step-backs.
In addition to adding new skills, strive to do the same with more speed, strength, accuracy and fluidity.
Being a great shooter is both physical and mental. Here is an instructive article from USA Basketball on Tips to Improve the Mental Side of Shooting.