First, use heavy decoys. My spread was made up of those now-priceless Herter's Model 50's -- heavy, heavily weighted and low-riding. No "water-keels" here! Second, connect your line to the decoy with a large snap-swivel; it may not make them ride better, but it'll prevent your line from twisting. And finally, use fairly heavy weights and enough line to allow a scope of at least two between the weight and the decoy -- for instance, 12 feet for 6 feet of water -- which will render the weights less likely to drag in the waves. And in case you don't know, that dragging can result in a massive tangle with other lines, thus royally confounding your duck-hunting day.
While divers will often circle a spread once or twice before committing, when they do commit they come in low and fast towards a particular spot in the spread: the opening mentioned earlier; it's sufficient in enclosed areas like the little pocket on Wallace Lake. In any case, the spread should be set in such a manner that the decoys will lead the ducks into a favorable shooting position.
In open-water areas, the time-tested fishhook pattern does this quite nicely. The bend of the hook -- the birds' landing zone -- should be just in front of the blind and padded with most of the decoys. Besides being the spot where you should take your shots, it allows the birds to settle in without passing over or too closely to other "ducks," as that would risk a collision in their hell-bent approach. Believe me, they know enough to try to avoid that.
The point of the hook should extend outward a bit and serve to form a blocking element to birds coming to the hook's bend. And the shank should extend downwind for some distance -- even out of effective shooting range -- to enhance the spread's visibility. I always liked to place two oversized decoys at the end of the shank, referring to them as "tollers." They did seem to get some attention.