It appears to be a common problem - equally among experienced and younger artists: shaking hands. My feeling: maybe half of all of us experienced issues with their arms shaking too seriously for sketching at least one time.
So I did the following collection of suggestions on how to overcome shaking hands or even how to get accustomed to it, if it cannot be stopped.
Although I've got to point out this first: in case you have shaking hands fairly often and have not done so already: go and see a health care professional!
Usually shaking hands are almost nothing a little more rest or cutting down on caffeine can not mend (later more on this). However shaking hands can also be a sign of some serious illnesses that require qualified medication.
Having said that, here are several natural remedies for shaking hands. Of course it's generally a great idea to live healthy.
So first reduce your coffee consumption. And do the same for beverages that contain caffeine like cola.
And then make sure you get sufficient sleep. Depending on your actual physical constitution 8 hours each day are a good rule of thumb. Also a quick nap immediately after lunch time can work wonders, too!
I know you don't drink greatly alcohol since this may aggravate your shaking, too. Only with regard to completeness: drink alcohol only occasionally and moderately.
Possibly this is a somewhat surprising discovery to you: trembling hands can be the response to a exorbitant sugar intake (often in conjunction with too much caffeine). So substitute the sugars with more healthy foods like vegetable and fruit.
And then it will help you if you get much more active. This could be frequent physical exercises or joining the local sports club as well as having longer walks.
Also a low level of Magnesium can cause muscle tightness leading to shaking hands. A indicator is when you get hic-ups or cramps. Therefore be sure to consume a good amount of veggies as well as salad daily so that you have more magnesium.
And then in case you are under medication this might be a factor, too. In this case - once again: ask your doctor. He may have an idea how to adjust your medication to lessen the shaking.
But what if you can't decrease the shaking enough to sketch without having problems?
Then you can implement these methods to sketch regardless of shaking hands:
To start with you will find in any nicely equipped art supply store what are known as drawing 'brigdes' - these are compact bridge shaped shelves made out of wood or acrylic. You place them across your drawing so you can rest your arm and stabilize your hand. The drawback: you can't do these extended and sweeping motions in exchange.
Second you may develop your drawing style in a way where its not necessary to sketch accurate aspects in great precision. So you learn to get a looser more flowing and much more forgiving style.
Finally you can think about utilizing stencils, french curves and rulers.
Most vital: don't become frustrated. Just imagine: old Charles M. Schulz (inventor of Charlie Brown and Snoopy) had Parkinson. Nonetheless he managed to adapt and compensate the shaking so he didn't quit drawing his comic strips till he retired (at age 77!).