Use fresh, vibrant basil for the best flavor and color. Toast pine nuts lightly to enhance nuttiness. Grate Parmesan cheese fresh for authentic taste. Add olive oil slowly to emulsify properly. To keep pesto green, add a squeeze of lemon juice or cover with olive oil before storing. Variations include using walnuts or almonds instead of pine nuts, dairy-free options with nutritional yeast, and adding herbs or spices for different flavors.