It is imperative for a leg-spinner to have a rhythmic bowling action, in order to impart maximum spin on the ball and to pitch the ball in the right area consistently. Run-up to the bowling crease is not something associated with the spinners but it becomes important for a wrist spinner. Shane Warne was an exception as he used to gently walk in his run-up; however, he had a big jump, which allowed him to put more force on the ball.
Finger spinners are recommended to bowl with a side-on bowling action. However, a leg-spinner can excel in his field with an open-chest action as well, like Mushtaq Ahmed, the former leg-spinner from Pakistan.
High-arm or low-arm
Another thing which differentiates a wrist spinner from a finger spinner is that the former is advised to bowl with a lower arm; whereas, the latter have no choice but to bowl with a high-arm action. A leg-spinner enhances his chances of spinning the ball more by bowling with a low-arm action.
Grip is extremely crucial for every spin bowler. A leg-spinner should hold the ball with his index finger and the middle finger, while the rest play a supporting role. While delivering the ball, you must rotate your wrist as sharply as you can.
Transfer of weight
Transfer of your body weight forward at the time of delivery is one of the most important things for a leg-spinner. This will help you be more accurate and get some drift in the air, which can make your leg-spin more effective.
In the start of your career, you must look to focus only on leg-spin but you have to learn to bowl a googly and a flipper with the passage of time.