Go buy the cheapest half dozen calls you can find, if you are like everyone else you won't like your first purchases and you may as well pay under $20 each for them than over $60. Then again, you may find "The One" in that bunch too. 😀
Otherwise, the advice skill trumps the call is key. The only addition I can add is to record your practice sessions then play back. Place the recording device 20 yards away as that will give you a good idea of what you sound like in the field. Using your own ears is not representative as you are so close that there is some auditory distortion due to the loudness. That may lead you into the wrong direction in your calling. If one looks, judges of any musical or vocal contest position themselves away from the contestant for that reason.
