Practicing the general drawing movements will always help, straight lines, curves, circles, etc.
But shaky hands can also be caused by a lack of electrolytes, or blood flow, or both, as well as too much caffeine.
Drinking water (especially if you normally don’t drink much,) as well as exercising your hands and arms will help.
This video →
(Link) best describes what I mean about exercising your hands,
And this page →
(Link) also has some good info.
It’s a pretty straight forward concept, if you strengthen your hands muscles,
You will improve the overall blood flow to the muscles and nerves in your hands,
And you will increase the stability of your hands, as well as your control for the small, fine movements, necessary for drawing.
And it will also help, if you stay away from caffeine, from there on, all you can really do is practice drawing.