RE: what is the most important...
If I had to pick one certain skill that has helped my success the most, I would say it has to be tracking. I don't mean following a blood trail, I mean deciphering and following tracks left by deer. This is an important skill, especially in areas where the deer population is low, such as where I hunt. Being able to tell freshness of a track, sex and size of the animal, identifying the tracks of individual deer, etc. are all key aspects of tracking that give the hunter an advantage. Whether I want to track down the deer or set up in a good ambush spot, reading tracks (as well as other sign) is a valuable tool.