While Parkinson's Disease is a very common and a real concern, "essential tremor" is 8-10 times more common. Additional causes of tremor include medications (particularly stimulants), head trauma, sensory loss, and, of course, true love. (JK, but any form of sympathetic stimulation can cause tremor.)
TOP DNC TIPS ABOUT TREMOR:
If your tremor occurs with action and/or posture, abates with rest, is symmetric, occurs further out in the hands rather than the whole arm, and is progressive over decades and not years, it is likely an essential tremor.
Too much of a good thing can be bad for your tremor. Yes, we are talking about caffeine. Minimizing this can minimize the amount of medication needed to control the symptoms.
You may already be taking something which can help. Some blood pressure, headache, and pain medications can be used to treat this problem.