Time in the field helps, too. Along with wearing out a heckuva lotta shoe leather.
And slow the heck down!!! Spend three times more minutes looking (binoculars, spotting scopes, bare eyeballs) as moving. Move quieter. NO, QUIETER THAN THAT! Never stand in the open, always "tree up" (stand next to something larger than you or capable of covering you with a shadow, or breaking up your outline), and never make sudden movements.
Also, if you find a trail with deer prints, you can always sit on it. A rule in fishing is "Moving water, still fish. Still water, moving fish". Well, the terrain don't move any too fast, so the deer generally are moving at least some of the time.