I would not consider myself a turkey hunting expert by any means, and I have figured out a lot of things that don't work... and a few things that do work. My experience has been that mouth calls are inexpensive enough that you can try a whole bunch of them and start to figure out what you like and what works for your mouth. Also, if you can, go hang out near a flock in the off season and see if you can get close enough to hear the birds, especially a group of hens. IMHO, there is absolutely no video, podcast, CD, or any other substitute that will teach you how the birds REALLY sound like being out with the birds, hearing how loud or quiet they are, how the sound travels in the outdoors, the cadence, and the body language of the birds as it corresponds to to the type of sound they are making.