When I address a jump shot, in many ways, I treat it like a regular shot in the regard that you must visualize what you want to happen before you shoot it. Alot of people make the mistake of cueing to high on the object ball, more than is necessary for a standard jump. The rule is usually that you cue the higher part of the cue ball for a shorter distance jump. It produces more height. You can shoot straighter through the cue ball, of course elevated, for having the cueball jump a longer distance. Always when you jump, concentrate on making the ball. I know too many people who are just starting to jump that only try just to hit the ball, and sell themselves short thinking that they do not have the ability to pocket the ball, like it is too tough. Start by jumping the ball to make it everytime. Try not to be just satisfied to hit the ball.
The first good jump to practice is parallel with the line through the side pockets. It is a short nice jump, and is also good one when working with the dart throwing jump. For those jumping more of a distance, I like having people start with placing the cueball close to the short rail and putting the object ball near the side, to make the ball in the far corner. Placing the cueball when near the head rail makes it easier by placing your bridge hand on the rail, elevating some for attempting the first couple.