A lot of people will say you can't call a wood duck. Honestly, it is easier to just be where they want to be, but I have, 100%, had them respond to a call both while flying and on the water. They seem to swim to a call more willingly than they'll fly to a call. Big thing I learned from the guys who have been teaching me is the flying wood duck call is about useless for calling them. They just ignore it. When I had them respond I was doing the clucks and purrs and that squeal they make while sitting on the water.
I have wood duck decoys, but I've also had them land in a bunch of mallard decoys, so I'm not really sure whether it matters or not. I figure it couldn't hurt and put some out if I'm set up near a swampy area.