You can choose different citrus to use in the dressing.
Store vinaigrettes in a jar or other container with a tight lid so that it's easy to shake it up again when you need it.
Generally speaking, any oils labeled "vegetable oil" or "salad oil" are fine for making a basic vinaigrette. You could also use any light, neutral-flavored oil like safflower, canola, or soybean oil.
Ideally, you'd prepare the vinaigrette in advance and then let it sit for anywhere from 1 to 3 hours. Just don't refrigerate it during this time!