Hey my friend, contrary to some of the suggestions posted, by far and away the best approach, to permissions, is face to face with the land owner. First of all, you should find a property that has what you are seeking then inquire about hunting, standing at their front door. No sense asking for permissions that don't hold the game to harvest. It is much harder for them to say no, when you've spent even 2 minutes "chatting", rather than with a phone call or any other type of remote interaction.
I hunt big game, waterfowl, upland game, fish, varminting, and more recently pest control. I would say 50% of my hunting is by permission and is the result of this method described. Most of my buddies are amazed at some of the hunts I have put together, just for asking...and typically it is better to gain permission without offering compensation up front, as it sets an atmosphere of friendship rather than a business negotiation. After the hunt, provide a token of appreciation and watch things snowball. I have permissions where my farmer let's me keep my trailer and use their power and water N/C. I have another permission, where I hunt geese and after a hunt on my birthday, I got to my truck and the landowner had left a birthday cake and pizza in the sleeper.
These are the permissions that you want to develop and as word gets around, that you are respectful and a good guy, you'll have more properties than you can hunt. Never hesitate to name drop...this means if you meet a land owner and even if you don't get permission, use his name and give the impression that you know something and some people in the local. The old "one of the boys" ploy. Good luck and good hunting!
Steve