All the previous suggestions are going to help you out. You are already getting some good advice... and I guess I can' t help but to throw in a bit of my own advice.

A good caller produces birds, a mediocre caller flare' s them. And the only solution is to practice. And practice. And practice.

For small ponds, I really like to keep my spreads small, call soft and let the motion decoy pull them in. Wait to shoot until they are completely in rage. Long shots are bad anywhere, but spooking/educating the ducks frequenting a small pond will dry up your hunting opportunity.

Good Luck!