A good vinaigrette is all about simplicity. Grab a bowl, whisk together some oil and vinegar, add a pinch of salt, and that's most of the work.
The secret to a good vinaigrette is the ingredients. The better quality of the ingredients, the better the end product will me.
You'll have to give your arm a good workout. Thoroughly blend the oil with the watery vinegar. When properly emulsified, the ingredients are suspended throughout the mix. A broken vinaigrette will have clear separation between the oil and the vinegar.
After that, all you have to do is add whatever flavors you prefer. Additions can be as simple as a pinch of salt and pepper, or as complex as honey, fresh herbs, or minced shallots. Store homemade vinaigrette in a covered container in the fridge for 3 to 4 days. Stir well with a whisk before serving.