If you're going to do any duck call, you must first learn the single quack.
Whether you're new to duck hunting or are a seasoned veteran, mastering the single quack is paramount to all duck calls.
Watch this video and get a breakdown on how to do the single quack and open the doors to many more calls.
The key to doing this call right is drawing your power from your diaphragm, not your chest. As the air comes through your chest into your throat you want to relax. Don't push out your checks, keep them tight so the air flows right into the call.
Did you see how the call is supposed to be held? Pretend like you're holding a golf ball and keep your hand relaxed.
When making the call you want to grunt "like a caveman." The best time to use this call is all the time, as it simply announces to ducks that another one is present. Knowing this call will lead to more kills, that simple. Take this guy's advice and practice this call anytime you can.