I was taught to do the "last bite" with a hemlock sprig by the leader of our gun hunting group (the father of a college friend) in 1980 and have kept it up. I still do this, after giving a prayer of thanksgiving to God and a prayer for the deer's sake. The deer gets a sprig and the hunter gets another dipped in the blood and worn in his hat brim for the rest of the hunt; or at least back to home. I understand this is a Germanic ritual. His last name was Bristol - hardly German - but it could have been passed along from who knows who in his past.
Note the sprig in this year's doe's mouth. This, for me, was deer #39 and, amazingly, EVERY time I have shot or arrowed a deer there has been a hemlock tree within a few yards. I just find that interesting.
Another tradition, that I think is brilliant, is that you do not clean your fist deer. Someone else always did that in our group for a newcomer. Seeing as how usually the first timer was shaking like a leaf this was a great plan. And then they always had a demonstration for how it should be done.
I don't really have a bit of "lucky" or long-time gear that makes the hunt. Though last year I dug a Snicker's bar out of my pack to munch on and it was the color of cork and tasted like a tongue depressor. Have to remember to rotate the inventory.