If you do any pre-season scouting, look for droppings under trees; the fresher the better. It' ll give you an idea of the area they may be roosting in and where to be to listen and watch.
Another trick someone posted here a while back. (Apologies and thanks to who ever posted their grandfather' s trick) When the flock is flying up to roost for the evening flap your hat and hit your leg a few times. In the morning before fly down, set up at that spot. At fly down the flock may come to investigate the " orphaned" turkey they heard the evening before.