When I was younger I had a fear of heights. I would get gripped when on the edge if you know what I mean. The I picked up bridge jumping and rock and alpine climbing in my teenage years and today I can proudly say have have 0 fear of heights. Face you fear head on. When I was learning to rock climb a friend suggested I fall on the rope. (I'm not suggesting you fall out of you tree stand to see that you safty harness works, assuming you wear one.) This was a huge confidence builder for me. Knowing that I was secured to the ledge by a rope that would catch me if I fell gave me tha ability to concentrate on the task at hand, Climbing rock.

If you know your harness will catch you you'll have the peace of mind to concentrate on the task at hand, Hunting.

Good luck and keep at it.