I’m starting to make my own salad dressing.
One, It shouldn’t be TOO fattening.
Two, It has to be a base of vinegar and oil.
What is the percentage of vinegar to (olive) oil.
Any one have a (Secret!) familly receipe? 
Two parts oil to one vinegar is a good starting point, but I find that vinegars vary significantly so you should do it to taste. Add salt as well.
There is an Italian saying that it takes 4 chefs to make a good dressing: a spendthrift with the oil, a miser with the salt, a judicious one with the vinegar, and a patient one to mix.
If you are worried about calories, I would suggest tossing the salad well with just enough dressing to lightly coat the leaves.
The typical proportions for a vinaigrette are 1-3-9. That is, 1 part mustard (mustard stabilizes the emulsion), 3 parts vinegar, 9 parts oil. In practice this comes out to 1 teaspoon mustard, 1 Tablespoon vinegar and 3 Tablespoons oil. I typically double this for 2 people, and have a bit leftover.
In practice, you may have to add a bit more or less oil, depending on the acidity of the vinegar and your personal preferance; many cooks recommend a 1:4 relationship between vinegar and oil. Expirement, see what you like.
Forget recipes. Have some fun! Go and buy a few different types of vinegar and a few different types of oil. The basic combo is red wine vinegar and a tasteless oil like canola oil. Most people welcome at least a portion of the oil be olive oil - however, using all olive oil may not be to everyone’s liking. It tends to feel heavy IMO.
Also feel free to add things like garlic and fresh chopped herbs. Lemon and/or lime juice can be used in place of some or all of the vinegar. Always add salt at the finish - it’ll taste bland until you salt it up some.
Basic technique:
In a small bowl, whisk together the mustard and vinegar. Sloooowly add the oil in teeeensy tiny drops, whisking all the while. Once the emulsion starts (that is, it starts to thicken) you can add the oil a bit faster.
Once you’ve added all the oil, add your salt and any other herbs/spices.
I also use different types of mustard - honey mustard, dijon, dijon with horseradish are all favorites.
Use the best olive oil you can find (or afford). Extra virgin at the minimum; anything else as your fancy strikes. Personally, I’ve become fond of calamata olive oil, but I also like almost anything Portuguese. You’re gonna eat it, not cook with it; you want some flavor in the oil itself. Olive oils can be flowery, peppery, even slightly sweet…they’re every bit as complex as fine wine.
As for vinegar…play around. Wine vinegar, champaign vinegar, sherry vinegar, rice wine vinegar, balsamico…just don’t attempt to use that half-gallon jug of white or “cider” vinegar.
Herbs as desired. Garlic, ditto.
2/1 or 3/1 ratio of oil-to-vinegar is normal, but it’s really all “to taste”. A bit of mustard helps hold the emulsion, and a tiny pinch of sugar can really bring out the sublety.
Yo, Athena ? Marry me.
i use 3 to 1 vinegar to oil, but in that fraction, I count my mustard as well as the vinegar.
What I always do, is take my vinegar, roughly chop 2 cloves of garlic, and use a hand-blender to chop the garlic into the vinegar(don’t do it with the oil, it’ll get all screwed up.)
Then add it to the oil, add spices to taste. have fun. try honey mustard in there, try dijon, try a half teaspoon of sesame oil…it’s all good to me…just make sure you blend the vinegar and garlic together.
Sorry - she’s taken. 
Taste your vinegar. They vary a surprising amount. Some are much more acid than others. I finished one red wine vinegar and made horrible dressing until I discovered that the new one was much milder.
If you’re prepared to try things other than vinegar, give verjuice a go. Mmm… fruity.
giggles at the boys