I know it's a little late for this response but in the past we have planted Either ***anese Millet, corn, or Sorghum (Milo) around the pond. Anything that will provide a good food source will be a good attractant.It's kind of late in the season for planting so a good thing to do is maybe spread some milo seed in or near the water.
Also some of the other guys at our lease swear by leaving decoys out all the time. Personally I don't see this helping out much. one last thing is nearby foodsources. find out what is close to you.