Draw circles and ellipses in any orientation, tracing over the circle or ellipse to improve it.
Vary the sizes of the circles and ellipses. You’ll notice that your arm moves differently if you do that. You will tend to do the smaller circles with your fingers, the larger ones with your wrist or elbow even maybe, or even your shoulder.
Try to draw from the shoulder or elbow as much as possible, for longer, confident strokes.
Feel free to hold a cup or glass in front of you to see what an ellipse or circle looks like.