My Basic Salad Dressing
Take a little mason jar (or a salad dressing shaker), add 2 parts EVOO, 1 part vinegar, a small spoon of dijon mustard and that's the base. Shake it vigorously before serving to emulsify. Pour over salad and toss.
I will sometimes add salt and pepper to the mix. Sometimes I'll salt and pepper when I put the salad together. I will often add fine diced shallot or garlic to the dressing. I'll usually add dried oregano, "crushed" with my hands before adding to the dressing.
For vinegar I mostly go with a good balsamic. I might do red wine vinegar or white wine vinegar or maybe even apple cider vinegar. Instead of vinegar you can use lemon or lime juice. Those taste great!
I think some people do 3 parts EVOO to 1 part vinegar, but I'm a tangy guy. With that base of 3 ingredients (oil, vinegar, dijon), you can go many different directions. And you probably don't have to include the dijon. It's not so much for flavor as it is for helping the emulsification process because science.