Make your own salad dressing
Put a third of a cup of vinegar into a blender or food processor, turn it on, and then slowly pour in two-thirds of a cup of oil. Add whatever herbs and spices you like before or after you start putting the oil in.
You pour the oil in slowly to "emulsify" the salad dressing—in other words, to mix the vinegar and oil together when they don't really want to be mixed.
If you're going to refrigerate the salad dressing, don't put more than a third of a cup of olive oil in it. That will make the dressing thicker after you refrigerate it, which is nice if you want a thick and zesty effect, but too much olive oil will make the dressing gloppy after refrigeration. I use 1/3 cup of olive oil, some sesame oil, and then peanut oil or canola oil to make up the rest of the 2/3 cup. There are all kinds of oils out there to try.
There are also all kinds of vinegar to try. Balsamic is nice, but can it can overpower other herbs and spices, so for my third of a cup I sometimes do part balsamic and the rest something lighter like rice vinegar.
Spices: dry mustard, fresh or powdered garlic, fresh or powdered ginger, dry or fresh oregano, any kind of salt or pepper that you have around; just look through your spice rack. Putting things like fresh herbs in earlier will get them liquified with the rest of the dressing, so put them in later if you don't want a completely liquified dressing.