The J, or shank, should be downwind of the pocket. Make sure the outside decoy of the J is no more than 35 yards from the blind so the ducks won't land out of range. Coot decoys, set back in the shallows near the blind, achieve the same purpose. Early season setups can utilize moderate to large spreads, depending on location and competition. Three to four dozen decoys work for larger lakes, marshes and reservoirs.
Small potholes can get by on less.
One big mistake many hunters do make early in the season, however, is setting up in the wrong spot. Preseason scouting can make the difference between filling a limit or just watching decoys bobbing in front of the blind all morning. Spend a few days on the water before the opener, watching the ducks from a distance to determine their preferred areas. Later on in the season, experience dictates the best areas for successful setups. Avoid light decoy lines, as they may be spotted from above.