The best way to call is as little as possible. 9 times out of ten I have ducks flying into my dekes without a call being given. However, if you have higher flying ducks you may need to coax them in closer.
I usually give a hail call in two successions to ducks who fly close but keep going... this is kind of like saying "Please Come Back To Me" into the call. If they are kind of close and interested in my decoy spread I usually hit a short feeder call... kind of like saying "tika tika tika quack" and then remain still until I see the wings cup or back flap for landing. Also another feeder call to let other ducks in the area know I "found food" is tika tika tika tika quack tika tika quack. This makes them think that more than one duck is in the area feeding so try and change the tone of your tiks and quacks as you call.
use a good whistle call for your drake mallard.... don't blow into the call actually vocalize the sound "wheeeeeeeeet'' about 3 to four times in succession. you can also use short peeps in different tones for teal. Most important of all DO NOT over call... I've seen guys out there who didn't put their call down for over an hour and just called constantly. There is absolutely no need for it. All it does is create call shy ducks. Well, hope this helped you out. feel free to ask any other questions about duck hunting.