Basketball practice drills can be in one of two very broad varieties - those that focus on developing strong fundamentals, and those that focus on putting those fundamentals into action in a game situation. Fundamentals work when they are automatic - if your player has to stop in the middle of a game to mentally review how to shoot the ball, you can count on a short season and on watching playoffs from the stands.
Basketball shooting, like all the other skills needed to play this sport, needs to be ingrained into players' minds and muscle memories - it needs to be practiced, and practiced, and practiced. Proper form, solid fundamentals, over and over again, until players' muscles don't know how to shoot the ball any other way but the correct way.
The drills to follow will help your players learn that muscle memory. When you are introducing them, remind players not to focus on speed but rather on shooting technique - slowing down in these drills is fine, and generally a good thing, as it is the basic techniques of shooting a basketball that we are trying to build.
These drills do not practice shooting in game situations, but rather focus on proper basketball shooting form. If you want basketball practice drills that add in game situations, check out the Shooting Drills page - you'll find plenty of game situation drills there.
Shooting Against the Wall
Encourage your players to practice these drills at home whenever they can - the more they practice, the better their basketball shooting form will be.
These are drills that players can practice outside of practice sessions, but they should definitely be used at the beginning of each season during practice to teach and reinforce shooting form and technique, before moving on to more complex, faster drills that add in game situations.
The better their form is from the beginning, the more ingrained that form is, the better shooters they will become.