If you've got a tremor, whatever the reason, you picked a good tool to be working with, the crossbow. Now all you have to do is figure out how to operate it with a rest.
In a raised stand, just make sure you get a stand with a shooting rail.
On the ground, look into some sort of shooting stick.
You'll do fine.
BTW: Dont' take any guff from guys that call crossbow a lousy way to take deer. It's perfectly legit. I was a compound bow hunter for 25 years and had to give it up, because my shoulder went bad. I switched to a crossbow, and documented the transformation on this forum Crossbow really is not my cup of tea, but it is not the unfair advantage that some would make it out to be.