Another good place to learn to call is believe it or not the Reifel Island bird sanctuary. I take my kids there all the time. They like that I can "talk" to the ducks.
Sometimes calling ducks less is more. They are opisite to geese. DU has some good videos. I use the single quack and the feeding chuckle. I make my own calls and I go down to Mcaurther Park in Kamloops to try them out. Just listen to the duck and talk back to them.