When teaching younger players how to shoot, I usually start with the release and follow through. These are a highly important aspects of a shot but they're something young players often forget to focus on. These players' shots look different every time and they don't build the consistency necessary to become a great shooter.
I like the guide hand to be close to the release position, only coming off the ball right before the release. Shooting hand should be pretty relaxed with fingers spread on the ball. They should be just curled over the rim on release. It's important to stretch your fingers when they tighten up!
Shooting elbow should finish above the shooters eyes for good arc. Usually eyebrow level is about perfect.
Young players should hold their follow through in perfect release position for at least 3 seconds after every shot. With some newer players, they might need up to 20 seconds while building their shooting mechanics. This will make the release and follow through feel like second nature.
Pictured above: Here's an example of a shooter just after release. Note the finger tips are through the rim. Also, the shooting wrist, elbow, shoulder, and hip are all aligned on target during the release. The shooting elbow is also just above eye level, to promote proper arc - which is very important and often underated.
Basketball Shooting: Why is arc so important?