Toast walnuts in a dry skillet over medium heat for 3-4 minutes until fragrant, then chop and add at the very end to maintain their crispy texture instead of allowing them to soften in the warm pasta.

Save at least 1 cup of starchy pasta cooking water before draining—use 2-3 tablespoons to emulsify with the butter and lemon juice, creating a luxurious coating that clings beautifully to each strand.

Always zest your lemons first while they're whole and firm, then juice them afterward; the zest provides concentrated bright flavor while fresh juice adds acidity and prevents the dish from tasting one-dimensional.

Remove the pan from heat before adding cold butter cut into cubes—this technique creates a silky emulsion rather than greasy oil, resulting in a restaurant-quality sauce that coats the pasta evenly.

Salt the pasta water generously (it should taste like sea water), then season the finished dish to taste just before serving—this layered approach builds depth and ensures the delicate flavors aren't lost.