The most common way to use oils is as candle dressing. Several methods have been published as to the proper way to dress a candle. Usually the methods focus on either a certain way of drawing an energy through the candle or banishing an energy through the candle. To invoke or draw an energy in, concentrate on the intended purpose and rub the oil into the candle from the wick to the base in a deosil manner. To banish something, rub the oil from the base to the wick in a widdershins manner while visualizing what needs removal.
Oils are also great for self-anointing, with or without a specific purpose.
I made underneath my altar for days when I have a little trouble dropping into meditation or reverence. I chose these ingredients because they're mostly catch-all power and protection herbs that usually only serve to enhance any other working I might choose to do. I anoint myself by dipping my fingers in the oil and drawing a pentacle on my forehead, rubbing my hands and rubbing my feet in the oil. Sometimes I say a quick prayer of dedication to the gods while I do this. It's easy to relax and meditate on the energies in the oil mixing with my own and then dropping into a meditative state.