I used to combat this by layering the sinkers as I assembled the salad, ending with the heavy garnishes on top. But by the time the second or third person was served, most of the garnish would have migrated to the bottom, meaning the next person in line would have to do a fair amount of fishing to get a few tomatoes with their leafy greens.
I soon discovered that a shallow bowl or rimmed platter was the way to go with these kinds of salads. Not only did it solve the sinker problem, but it easily allowed my guests to see what was in the salads. The pretty garnishes were scattered throughout the whole salad and could be slightly arranged to show off their color and shape.
The greens can be first tossed in a bowl and then transferred to the platter, followed by the dressed garnishes. But I'm a fan of not creating extra bowls to wash up so I just arrange the lettuce and garnish on the platter, drizzle with the dressing and then toss slightly as I'm serving the salad.
(Images: Dana Velden)