To be an effective shooter you should practice regularly, daily is preferable. You should also have a set practice routine. Here are some simple steps to help you develop a shooting practice plan: warm up, shot selection, goal setting, and focus.
Start each practice session by reviewing and practicing the technically-sound movement pattern for the basic jump shot (see my tip the Basic Jump Shot).
An Exercise. Stand one short step away from the basket. Get set by checking your body stance, the ball/hand relationship, and the ball/body relationship. Once in the correct set position, shoot. If you make the shot, take a step away, and repeat. Each time you make a shot, take a step away. Continue to do this until you reach the limit of your shooting range.
Each time you shoot, provide yourself with feedback, that is, try to measure the degree to which each shot mirrors the technically-sound movement pattern. For example, did you keep your forearm vertical?
Each time you miss, start at the beginning. Do this exercise for about 5 minutes.
Practice only those shots which you are likely to get in the game, such as shooting off a dribble or after receiving a pass while stationary or while ending a cut (learn to simulate receiving a pass in these two situations). Take shots from locations on the court similar to locations from which you will be shooting in games. Make sure you shoot each shot at game speed, that is, learn to shoot as quickly as you can.
It is important that you have a set practice target for a shooting percentage. For example, I expect my players to make 7 of 10 shots (70%) consistently from 15 feet to the three-point line and 5 of 10 shots (50%) from outside the three-point line. The minimum target for free-throw shooting is 70%. Players who do not achieve this standard in practice are not considered to be shooters.
Each time you take a shot, you should be completely focused, as explained in my tip Shooting - Essential Mental Capacities.