Leave all your calls at home. If there are turkeys there, they will leave sign. Calling to them only educates them. They will get so they won't even answer your locator calls. If you want to hear them gobble, get up early on a sunny morning and listen.
Learn the terrain like the back of your hand. When you set up in the dark, you want to know that there are no obstacles between the turkey and you.
Get to know their travel routes. "It's easier to call a turkey if he's going there anyway."