Listen to UncNorb, he's tellin you right! As he said, and it's a crucial part that makes ALOT of sense when you think about it but the majority of things in the woods are vertical. So what you are looking for is horizontal lines. Many times those "horizontal lines" are in fact a deers back as it's standing still looking at something. Also look for movement, a flicker of a tail or ear. As was said, move s l o w and when you think you're moving slow enough, SLOW DOWN SOME MORE! Use your binoculars to checkout EVERYTHING you see.
A steady breeze helps in dry conditions as it can mask your steps in the leaves. But obviously rain, snow makes it far easier (if you are hunting in snow then consider a single bed sheet with a few streaks of dirt/black on it to wear like a pancho to help break up your outline). I also prefer to stop in the shade against a tree instead of broad daylight. Your binocs, your scope, your gun can make a glint or outright blinding shine at 100yds that you have no clue about. Also, being in the shade can help conceal your movement as well because the light and color contrast effect is lessoned in shadows. Deer are quite able to see a mans outline standing by itself, but if you are leaning against a tree or in a clump of saplings/brush they likely won't give you but 1-2 glances and if you aren't moving they'll think nothing of you.
Walking wise, I prefer soft rubber bottom boots (classic LL Bean hunting shoe, duck shoes etc...) for stalking. You shouldn't be walking or taking a normal stride when stalking & slip hunting. Instead, step NO further than your heel in front of the foot you are standing on. Then as you do take steps DON'T step in the regular "heel-toe" pattern. Instead, step with the ball of your foot/toes down on the ground first then s l o w l y "roll" your foot down slowly. This method allows you to feel sticks under your feet and you can then move your feet around without crunching those sticks. Also a faint "cruuuuuuunch" of your foot slowly & quietly mashing down into the leaves is a much less disturbing noise than a full out CRUNCH from a regular pace footfall as you if you were walking at a normal pace through leaves.
Look for movement, the trick is to see them first. And be careful, in most areas you aren't likely to run into a single deer. (if it's solo, there's a good chance it IS a buck) Look for others and keep their eyes & ears in mind as you move into position. I've successfully stalked a few deer with my bow over the years and it an absolute blast when the conditions are right. I particularly like to get on an old logging road and just start easing along, looking as far in front of and beside me as I can see through the woods hoping to see any deer headed towards me before they see me. I'd be in position & ready by the time they crossed the road in front of me. (Stalking deer in a field CAN be productive IF they are staying in one general area and you can sneak around about 10yds inside the woods & get into position without them knowing it, but many times deer in fields aren't alone and you end up being busted by one further back in the woods or one that came up behind you and you didn't know it!
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