Best does not imply but rather specifies- one. Now, I know that there isn't only one trick of the trade that makes us successful because obviously there are many used in combination that do. However, if you had to pick one to contribute to this thread, what would it be? If everyone pitches in one, eventually we will get a nice collection of the best of the best.

Mine is one that I learned a few times already but had to learn again this year... Never discount any noise in the woods as not being deer. This year during the gun opener, I arrowed a buck. 2 min later I heard a "squirrel running back and forth and in circles". When the "squirrel" showed up under my stand I wasn't ready resulting in a missed opportunity.

What's yours?