Traditionally vinaigrettes are 1 part acid to 3 parts fat (read: 1 Tbsp | 15 ml vinegar to 3 Tbsp | 45 ml olive oil). To make a punchier salad, I prefer 1:2 (read: 1 Tbsp | 15 ml vinegar to 2 Tbsp | 30 ml olive oil) or even 1:1 in some cases of richer foods. You can add anything you like to vinaigrettes, like onion, garlic, or mustard.