Most of the salad dressings for my recipes are variations on or at least start out as a vinaigrette, simply an oil and vinegar dressing with some other ingredients added. This can be varied in so many ways, as you will see in the recipes. Here I am giving some of my general thoughts.
The generally recommended proportions of oil and vinegar for a vinaigrette are 3 parts oil to 1 part vinegar (or other acid). You might vary this a bit depending on how prominent you want the vinegar to be, but I would not stray too far from this tried-and-true formula. For a main course salad for one, I will use 3 tablespoons of oil and 1 tablespoon of vinegar.
For the oil, I am generally using either vegetable oil or olive oil. For the vegetable oil, my choice has been canola but of course use what you prefer. And there is such a variety of olive oils from which to choose, so use your favorite(s). I like to use the olive oil for many dressings, but for some, the more neutral flavor of a vegetable oil seems to be a better choice.
Many different kinds of vinegars are available that give distinctive tastes to the dressing. I use at least red wine vinegar, white wine vinegar, apple cider vinegar, rice vinegar, and balsamic vinegar. Other acids, such as citrus juices, can be substituted for the vinegar. A lemon juice vinaigrette can work especially well with some seafood salads.
Herbs, spices, or other seasonings are generally added to a vinaigrette. The sky’s the limit here, with the seasonings taking the dressings in many different directions.
Other condiments are also often added. One is very commonly used and deserves special mention–mustard, usually Dijon mustard. This serves two purposes in a vinaigrette: The mustard is a great flavor addition and it also helps the oil and vinegar combine or emulsify.
Some formal recipes for vinaigrette suggest combining all of the ingredients except the oil in a small bowl and then whisking while slowly pouring in the oil. For me, this is overkill for the small amount of dressing I am making for a salad for one. I am perfectly happy putting all of the ingredients together in the bowl and whisking vigorously with a small wire whisk. Or put all of the ingredients in a small jar and shake.
My salad recipes will include all manner of variations on the basic idea of a vinaigrette. Here I’ll give my take on a nice, basic dressing that I like for all different kinds of salads, sized for a single main-course salad:
3 tablespoons olive oil
1 tablespoon red wine vinegar
1/2 teaspoon Dijon mustard
1/4 teaspoon herbes de Provence
fresh ground pepper (I like to use fresh ground pepper from a pepper mill, and it’s impractical to measure, so use your judgment and taste.)
Combine ingredients and whisk in a small bowl or shake in a jar. That’s it.
My wife was going to a gathering where everyone was tasked with bringing food for the supper. Her assignment was to bring a salad. She put together a bowlful of greens and other nice salad stuff and asked me to make my vinaigrette to take for the dressing. I made this basic recipe (obviously in a much larger quantity). She came home and said everyone raved about the salad and dressing. Sometimes simpler is better.