In a small jar with a tight-fitting lid, combine the olive oil, lemon juice, and mustard. Crush or chop the garlic finely, adding as much or as little as you like. Similarly with the herbs, add as much or as little as you prefer of basil, dill, rosemary, and/or tarragon. (Some herbs are stronger than others and will dominate the flavor.) Add salt and pepper to taste. Shake the jar vigorously and pour mixture over your salad.