We have a garden full of salad lettuce, but our supply of salad dressing dry mixes (add oil and vinegar or mayonaise) is running out. We can buy mayonaise. Does anyone have suggestions for adding spices for making one's own dressing?

olive oil, vinegar, oregeno, basil, salt, pepper, sugar. Use balsamic vinegar if available.

Olive oil, balsamic vinegar, soy sauce and tomato paste. A squeeze of lemon, a dab of dijon mustard maybe. First add the vinegar to the paste and whisk, otherwise you get a lumpy puree. Add everything else to taste. Bon appetit!

Not sure what sorts of things in the allium family you have in Ethiopa, but roasted garlic is one of my favorite dressing bases. You can "roast" it vigilantly on the stovetop over medium heat---don't peel the garlic, just separate the cloves of a head or two and shake the skillet fairly frequently, cooking for about 15 minutes or until very soft and a little browned. This mostly kills the "bite" garlic has in raw form and brings out a creaminess and sweetness that makes the most amazing dressing. With two heads of garlic you can make this dressing:
1/4 c. roasted garlic (yes, that much)
3 Tbsp. olive oil
2 Tbsp. water
2 Tbsp. apple cider vinegar
1 Tbsp. dijon mustard
1/2 tsp fresh minced thyme, or a pinch dried
1/2 tsp. salt
1/8 tsp pepper
Blend in a food processor or blender. Keeps up to 4 days in fridge.

I like to add a small amount of minced (raw) shallot or red onion to whatever dressing I am making; without it they just tend to taste shallow and bland to me. A pinch of sugar can add balance, and any kind of whole grain or Dijon mustard also gives a depth of flavor and a kick.

1 part red wine vinegar
1 part dijon mustard (make sure you like the flavor of the dijon mustard NOT all dijon mustards are the same, some are bitter tasting and will ruin the dressing)
crushed garlic (to taste)

Thoroughly mix together and slowly add while mixing

2 parts virgin olive oil

In order to keep the salad dressing mixed, you need to mix the mustard and vinegar together first before adding the oil. This is the best salad dressing I've ever had. The recipe came from rural France.

A recipe for ranch dressing:

Texan Rose: Homemade Ranch Dressing

This stuff is delicious! You start with equal parts mayonnaise, sour cream, and milk soured with vinegar, then add spices. If you don't have sour cream you can use two parts mayonnaise instead.