Scouting is the key. If you are hunting large woods, it's hard to "scout" as they will see you before you see them. If there are fields and big open areas, you can glass from distances. The only way to tell if there are turkey around in big woods is to get out well before daylight and try to locate their roosts. Use shock calls like Crow and Owl as well as soft hen calls. It may vary several hundred yards from day to day but will give you an idea if they are around.
You can have the best gun, ammo, calls, and decoys. If there are NO turkeys, you won't get one. Find them first.