Learn to utilize the entire rim when shooting jump shots. I teach shooters to forget about distance and master ball placement. All the jumpshots and free throws you shoot are the same shots. In fact it's one shot because the ball must arrive at the same point in order for any of them to go in; hence you merely need to master getting he ball to that single spot.
Make sure that keep your elbow close to your body but not touching. Be sure that your shot reaches the height of one basketball above the backboard ( mid -range, trey & free throw). Turn your feet to 10 o'clock (right handed shooter) or 2 o'clock (lefties). This lines your hip up with the basket and allows you to shoot right down your hip on a straight line to the basket. Sweep your feet when you shoot (search on youtube for examples). Lastly, be sure to follow fully extend your shooting arm and through with fingers pointing down after releasing your shot. This tells the ball where to come down. Shoot high and straight . . . . sweep your feet . . . . follow through. When learning a new method of shooting, many athletes get discouraged because the start missing a bunch of shots. Do fall for that. Continue to shoot with this method until you are comfortable with it, and you will be happy you did.
Be honest with yourself about your strength level. If your current strength level suggest you stay within 10 - 18 feet of the basket, do so. Don't venture out for long distance shots just because you see your friends or a High School, College or NBA player do so. They have the strength to put it up from long distances with good form. Only put up long shots if your strength level dictates you can do so with good form. And proper form is one of the things that counts when shooting jump shots.
I would have you go to a wall. We would determine what is a comfortable stance for you and where your shooting pocket is. To be a great jump shooter the ball must go to your shooting pocket first before bringing it up to let it go. I would have you practice shooting against the wall, hitting a specific target. This enables us to work on stance, foot and body positioning, proper hand eye elbow technique and mental muscle memory without the stress of trying to make a basket. Once I determine you are ready, and it may not be in one session, then we would go to an actual basket to shoot. We would not go at game speed or worry about missing shots in the beginning. The most important things are the alignment of your body, elbow, hands and fingers, follow through and pulling from your shooting pocket.
Now I would explain the importance of "Feeding the basket and taking a cookie for yourself." See, the basket is very hungry. The only way to satisfy its hunger is to put the ball in the basket. Therefore everytime you score, you are feeding the basket!! Also under the basket attached to the rim is a basket of your favorite cookies. Therefore when you shoot you have to reach up high over the rim and dip your hand down to take a cookie. This helps you with the proper height of your shot and your follow through.
If you make a game out of it, you will enjoy going out and practicing as much as you can to become a better shooter.