Serve right away or chill in the refrigerator for at least 30 minutes to let the flavors blend.
Notes
Relish: For a consistent recipe some of the excess liquid in the relish should be drained. To do this, measure out 1 Tablespoon at a time and use the back of another spoon to lightly push the liquid out while it's still in the measuring spoon. Feel free to add some of the liquid to the tartar sauce after mixing and tasting.
Lemon juice: Start with 1 teaspoon. If needed, gradually add another teaspoon to achieve your desired tanginess.