Very important Jake... and a good point that I forgot to mention. The biggest tip I can also add is you seldom will see a whole deer standing there. I condition myself to look for deer parts or brown colors. The flicker of an ear or tail will often give them away and the brown outline of the back is another thing to look for.. If thick get down low and you might see some legs especially in a cedar or coniferous bedding area. For those people trying out still hunting don't get discouraged if all you end up seeing is flags. It is a numbers game and an acquired skill. All of a sudden you are seeing shootable deer and my deer sightings are often many more than the hunter who sits on a stand all day. I wouldn't recommend that kind of hunting unless you have big woods as I previously said. I have used this method of hunting with great success elk hunting too. They always have lots of eyes and noses though which makes it tougher. Terrain use to hide your approach and wind control are most important out west plus like Boca said using the binos. Speaking of binos get a bino halter which keeps them tight to your chest and always available.
In the northeast... benches, swamps and saddles are always a good place to spend time. I rarely will spend much time in the open hardwoods especially since there aren't many nuts this far north. Lots of people spend all day sitting watching an open hardwoods and I have found the deer will rarely cross them. Most of the time they will be along an edge of a defined thicker area which is where I hunt. I have shot a lot of deer and it is rare that my shot is more than 75 yds with most from 40 to 60.