Everyone wants to shoot like Ray Allen, but his advanced skill level is not achieved overnight. You have to put in countless hours of practice to develop good shooting form, build muscle memory and increase confidence in your shot.
The old cliché "practice makes perfect" is not entirely true. If you practice something the wrong way over and over again, it is still wrong. One of my former coaches used to say, "practice makes permanent, but perfect practice makes perfect." If you want to be great at something you need to learn it the right way and then spend hours perfecting it.
When performing basketball drills to improve shooting, it is important to do the same thing on every shot. You are essentially conditioning your body to repeat the motion so you don't have to mentally focus on it during games. The sequence for every shot should be:
Players shoot a variety of different shots in a game, depending on their roles in the offense: shooting off the dribble (one on one or off a ball screen); catch and shoot (when a teammate passes the ball to you); triple threat shots (mid range or 3 point line); and on the move (off a down screen, flare screen, etc.). All of these types of shots can be developed only one way—with perfect practice.
These drills are the tools you need to become a great shooter. Find a friend or teammate to rebound for you, and put in the work every day. You will be surprised at how much your shot improves.