You certainly have to find a call that you are comfortable with and fits your mouth. I really like Hillbilly custom calls. They work well for me and the sound is awesome. Keep practicing and it will pay off, and be patient. One suggestion, if you can find a CD of Tree Top Turkeys. It has recordings of live birds. I put mine in the cd player driving to work and practice,practice, practice.
Good luck and God Bless
Ray