These are the necessary steps in order to have a higher percentage chance of making the basketball in the hoop.
First you will need an official basketball. For men, the regulation size is 29.5 and for women the regulation size 28.5.
Depending on your dominant hand, place the ball in your hand with your palm facing up towards the sky and with the seams of the basketball horizontal to your fingers.
Once your hand is properly placed on the ball, spread your fingers as far apart from each other as if you were trying to grip the ball. With having your fingers as far spread as possible that should create space on the bottom of your palm between your hand and the ball. To know if you have enough space, you should be able to place a finger between the ball and your hand.
Now that your fingers are situated, you have complete control of the basketball when you're getting ready to shoot.
Turn your wrist and bend it backwards, allowing your arm to create a perfect 'L' shape. From your pointer finger, to your wrist to the crease in your arm and going up to your shoulder should be a straight line the highest percentage of the shot going in the hoop.
Once your hand and ball is in position to shoot, place your opposite hand on the side of the ball for guidance. Note* you want to place the ball next to your forehead so you have clear vision of the hoop.
The rest of your body should be parallel to the hoop or "square". Everything from your shoulders down to your feet should all be in alignment with the basket.
Along with your shoulders, your feet are one of the most important things to keep square towards the basket. If you're right handed your right foot should be a few inches in front of your left, and if you're left handed, your left foot should be a few inches in front of your right foot. A trick to know if your feet are properly placed is if you put them straight and square, and slide whichever foot forward a few inches. Ex. If you're right handed, your left big toe should almost be in the center of the arch in your right foot.
As you get ready to shoot, bend your knees. Bending your knees will take less pressure off your upper body allowing you to jump higher when you shoot.
As you jump, release the ball when you get to the peak of your jump. Flick your wrist as hard and quickly as possible releasing the ball giving it maximum rotation. You should follow through leaving your hand up with a ' swan' with your fingers as they should be when you flick your wrist.
To know if you have a good form, the ball's peak should at least be above the square of the backboard or above the backboard. When you land, land in the same place assuring that your shot was released straight.