One of the following:
1 Tbsp lemon juice
1 Tbsp rice wine vinegar
1 Tbsp white wine vinegar
1 Tbsp balsamic vinegar
1 Tbsp red wine vinegar
1 Tbsp sherry vinegar
1 Tbsp champagne vinegar

One of the following:
1 Tbsp maple syrup
1 Tbsp agave nectar

One of the following:
1 Tbsp water
1 Tbsp orange juice
1 Tbsp cranberry juice

One of the following:
1 tsp Dijon mustard
1 Tbsp sweet white miso

Zero to as many as you want of the following:
Dried herbs
Puréed raspberries
1 diced or sliced shallot

Put all the ingredients in a small prep bowl. Whisk with a small whisk or a fork, until the dressing emulsifies. If you are using "chunky" ingredients, you can also purée the ingredients in a small blender or small food processor to avoid the "chunks".