I hunted a reservoir this morning that is 98% iced up. (limit of ducks and 1 goose) Look for the spots on bodies of water where a creek or canal enters and you will kill birds. The area I hunted was about 300 yards long by 50 wide of ice free water. The trick is to make the decoys look natural and "resting." These areas are not feeding spots usually, they are more daytime stop for ducks and geese. Hide well and call soft, most of the birds will come in silent.
If you can find a creek or river near you that is holding birds, SCOUT it well. Most of the time you can be 100 yards off the right spot and just watch mallards drop on it all day. If you put yourself in the spot you have seen birds using, most of your shots will be 20 yards and closer.
Good luck and always put extra clothes in the vehicle. A winter morning wader fill-up can wreck your day real fast.
"No, there's no such thing as dedicated about it. You guys just like to kill stuff."