Can you tell me how to make a stable emulsion from olive oil and essential oils?

You need to add an emulsifying wax to reduce surface tension- olive oil and essential oils alone won’t make an emulsion.

You can use: Almond wax, BTMS, Cetyl alcohol, Cetearyl alcohol, Glyceryl stearate, or Candila and Carnuaba for harder, water-proof products.There are many more, but those are commonly available. You can also add Polysorbate 80 to the oils first, this will give them a smooth, clear blend, before mixing with the emulsifier.