There is no one right way to do anything. So it is with vinaigrettes. Mixed baby greens need a dressing very different from endive, pears, Gorgonzola, and walnuts. Arugula is best served with a simple dressing, different from a salad of spinach, Fuyu persimmons, and glazed pecans.
The main variables are the acidity of the vinegar or citrus used, the quality or type of oil, and your taste. What I have learned so far is that a good starting point for the vinegar to oil ratio is about 1:4. Imported vinegar may be stronger than domestic ones requiring a ratio of 1:5 or 1:6.
Lemon juice or orange juice is less acidic perhaps requiring a 1:2 or 1:3 ratio. I have read that French chefs prefer more acidic vinaigrettes.
These recipes are the clinical guidelines to use as a starting point for making vinaigrettes in your own kitchen.