Here are my Aunt Ann's tips for making smoked whitefish salad:
Whether you buy your smoked whitefish prepackaged, as I did, or from a deli counter, check to make sure that it is moist, not dried out.
She recommends sugar-free mayo like Duke's or Trader Joe's variety, not Hellman's which is full of sugar. You want a tart whitefish salad.
White pepper is more of an aesthetic choice than a flavor one.
Above all, let the flavor of the fish shine through.