Gather all ingredients and equipment. Drain capers thoroughly and pat dry with paper towel. Wash fresh herbs and pat completely dry.
Finely dice dill pickles into 1/8 inch (3mm) pieces. Mince shallot or onion as finely as possible. Coarsely chop capers and finely mince fresh dill and parsley.
Roll lemon firmly on counter to release juices, cut in half, and extract 2 tablespoons of fresh juice using a citrus juicer, straining out any seeds.
Add mayonnaise to mixing bowl with dill pickle relish, Dijon mustard, and Worcestershire sauce. Whisk until smooth and uniform in color.
Add chopped dill pickles, capers, minced shallot, fresh dill, and parsley to the bowl. Fold in until evenly distributed.
Pour in fresh lemon juice and add garlic powder, black pepper, and sea salt. Whisk thoroughly for 30-45 seconds until fully combined and creamy.
Taste and adjust seasonings if needed. Add more lemon juice for tang, salt for flavor, or herbs for freshness.
Cover bowl with plastic wrap or transfer to an airtight container. Refrigerate for at least 30 minutes to allow flavors to meld.
Remove tartar sauce from refrigerator 5 minutes before serving. Stir to reincorporate any separated liquids, taste once more, and transfer to serving bowl.