Last year I took 4 turkey' s from the same field---3 from the same tree. I had patterned them over the course of the first few weeks of the season and noticed that 2 to 3 gobblers would always show up in this one particuar part of the field. So I decided that the best thing for me to do was make sure I got up early enough to cross this field under darkness---set up---make occasional clucks and purrs---and wait. Paid off nicely three times.
In retrospect it was probably a combination of calling and ambush.
My normal pattern is to decide the night before where I am going to hunt in the morning (By that I mean deciding not only the property---but where on the property---usually a place where I have spotted gobblers recently). Set up there an hour to 45 mins before sunrise---wait until the birds begin to awaken---and make occasional calls for 1 to 2 hours. I rarely move before then. Sometimes I will use a locator call---mostly not.
This year I also got 4 nice gobblers---2 were as a result of this strategy. The other 2 I was lucky enough to creep up on (private property).