I would use a dozen to two dozen decoys. Get some teal decoys and either mallard or maybe gadwall. If you get mallards, just use the hens early season.

I usually only use a peep or whistle call, unless I know mallards are coming in. In terms of calling, I don't use unless I need to get the attention of the ducks, and hopefully when they are turning and not directly overhead.

It is more important that you keep still until the ducks are in range than how much you call. Keep the calling to mininum.