Learn to focus on the sound and to coordinate your hand movement with your ear.
Play these exercises when you have set up the theremin and have tuned it. To find the note, move your arm between your shoulder and the vertical antenna, as if it was attached to an invisible string. Collect your fingers together and keep the wrist straight, for more confidents. Play legato, controlling the volume on a comfortable level.
It is also advisable to learn Clara Rockmore’s exercises at this stage.