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.
Watch Steve Nash's workout. He spills pure gold through out this workout. Click here to download a PDF of his drills.
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.