RE: Cornfield tactics
If it's irrigated they may never leave the corn as they have food, water, and cover. We do three things when the corn is still in.
1) Spend some time watching them with a spotting scope to see where they are traveling between the corn and trees. Then set up by their trails. Also look for funnels or bottle neck. We have a place where there is a finger of trees that is like a funnel between the corn and trees. There has been more then one fight in our house as to who gets to hunt this spot.
2) If it has a pivot on it, the towers are a great place to take a stand.
3) If it's a windy day you can still hunt them. Use the gusts of wind to cover your movement. On a windy day the corn really makes alot of noise. Don't forget to play the wind.
As far as when the corn is out, we hunt the trails leading to the fields but set up futher back tring to get them before they get to the field. We also have a blind that over looks the field, which has been good also.