Get Zink's Waterfowl University DVD with the Zink power hen 2 which is a double reed call. It is very forgiving and easy to learn off of. The DVD on the other hand will teach you the basic's of how a call works and how to do a feeding call, quack, etc...
PS: record your self and play back...You will think you sound great, but when you play back you will find out you sound like a dying elk... Listen and tweak your air flow, lip placement, etc... You will laugh at your self at first but stick with it. It is like riding a bike.
I have actually felt the opposite. When I listen to myself call I think it sounds or but could be better, but when I record myself and listen to playback it sounds like what I listen to on YouTube. So I'm not too upset.