The dip will improve with time so making this a day in advance is no problem at all. Just keep it covered and stored in the refrigerator.
1 (8-ounce) container creme fraîche
1 teaspoon lemon zest
1 tablespoon freshly squeezed lemon juice
2 tablespoons chopped fresh dill
2 tablespoons chopped fresh chives
Salt and fresh ground black pepper
Stir creme fraiche, lemon zest, lemon juice, dill and chives in a bowl until well blended. Season with 1/8 teaspoon of salt and a few grinds of pepper. Taste and adjust with more salt/pepper to taste. Cover and refrigerate at least 20 minutes.