The ratio for a good vinaigrette is 3 parts olive oil to one part vinegar.
For a salad vinaigrette, or a dip for seafood or steak,
6 tablespoons of olive oil in a jar with 1 tablespoon of apple cider vinegar 1 tablespoon of lemon juice Add some salt and pepper some fresh herbs (dill is nice) and a little grated fresh garlic.
Shake up and serve, or keep in the fridge for up to a week.