Get out just before dark at fly up time. Listen for them flying into the roost and also listen for any gobleing in the spring time. Try to set up as close as you can to the roost with out spooking them.
Look for areas where they have been scratching recently for food to go to a few hours after they fly down but after they visit thier strutting area.
Look for strutting areas. They tend to be in open type areas where they can be seen "strutting" thier stuff. Sometimes you can see in the leaves where the wings were dragging on the ground in these areas. It will look like someone took a small stick and scratched a line in either side of the turkey tracks. Also you will probobly find some feathers that they knocked out while strutting.
Call very quietly to them on the roost and I like to really hammer the calling after about 8:30 with hen calls. I move around often when I am acting (calling) like a hen that is in search of a Tom.
Try to get an issue of "Turkey and Turkey Hunting" magazine.

hunter 777 summed that up perfectly....I pretty much do the same thing...I'll mark locations on my topo map where I heard gobblers and usually they will be in the same area once the season starts. Good luck

PSG, I read your post about changing up the calling according to the way the turkeys are responding and have to agree with you. I say I like to hammer the calling after 8:30 or so but that does depend 100% on how the turkeys are acting and I will only do that after I try a little soft calling first. If I tried that and they didn't respond then, I would try something more aggresive then....move on. Find a bird that will let you work him. He is out there somewhere.
You may call to a bird one day and he completely ignores you and then 2 days later he may come running right in to a single cluck. Just mix it up and see what works in the situation you are in.
Sometimes I move around and call alot and other times I just move around and listen a lot.

Defintiely! I would say Turkey hunting has offered me more "off-the-wall" situations than any other type of hunting. Thats why I love those Gobblers! big challenges await!