Welcome to NeuroTalk:

I looked on PubMed for you and could not find any papers on
CoQ-10 studies.

I did find this link however:
http://suite101.com/article/natural-...tremor-a387994

This link suggests, l-theanine. Dr. Blaylock MD also suggests it for other neurological conditions, like peripheral neuropathy.
This is a good brand (which I use also but not for tremor):
http://hsionline.com/2006/07/20/essential-tremor-2/

Low doses of beta blocker may help--often they don't cause as much side effects as higher ones.

Also some people have temporary success with Benadryl.
This is over the counter, but also alittle sedating. People with glaucoma or men with prostate issues cannot take it. It tends to lose effectiveness with time in some people.

Some people who are intolerant of gluten in the diet, have ataxia or other problems with the cerebellum. Going gluten free for 3 or so months may help if you are one of them.