Actually, its easier than you would think.
Conditions are the key.
Mid day,
Wind.
Keeping the wind in your face.
Never step into a row before peeking.
Wait till the bulk of the cornfields are gone. (1 per mile or less)
Camo up different than you would for woods, obviously. bit go light colored on top because the deer is laying down and you are close, so you are way above it. Think of how you would camo if you were against the sky.
Ive been hunting in the corn fields for over twenty years. both with a bow and a gun.
The keys (other than the ones noted above) are:
With a gun, you can shoot down the row. Typical shot is a 20 yd neck shot.
With a bow, you always shoot cross rows. Usually 3 or 4 rows away. Typical shot is 3-4 yds into the body cavity. When you let it go, be prepared to move, as they typically take off crossrows initially.
Adjust your approach to the way they are laying. You can approach from any one of 270 degrees, just cant get upwind.
Sometimes you are playing the wind to a within few feet.
Take your time. There is nothing as exciting as seeing the first patch of fur or the big eyeball at 15-20 feet! Then you start looking for the lane to shoot thru.
If gun hunting, go in the fields one at a time. Bow hunting can utilize more than one hunter, but it should be decided where you can and cant go ahead of time.
It used to be easy when the rows were 36 inches. Then 30"s came along and it makes it so much harder. BUT, with the advent of Roundup Ready corn and GPS guided planters,that has improved the ability to hunt 30 inch rows. Dont even think about 20 inch rows. Its impossible.
Toad Smith from Sibley Ia. wrote a book and produced a video outlining how the succesfully hunt in the corn. I have both the book and the video. It has been out of production for many years, but occasionally one of them pops up on the auction sites. I wont loan out the video, for damage reasons. If anyone is interested in the book, Ill get it back and send it out.
Here is a discussion from a couple years ago.
http://www.fishingminnesota.com/forum/ubbthreads.php/topics/1163357/1This is going to be a great year to hunt in the corn!.