ELEMENTAL MAGICKis a basic tier of magickal correspondence to the Western Tradition. All things on Earth, and all magickal goals can be categorized as a function of the powers of Air, Fire, Water, Earth (the cardinal elements which correspond to the Four Directions, and sometimes to Spirit alone, the Fifth Sacred Thing, which is composed of and at the same time the origin of the Four.
In other words, any type of magick you might endeavor can be accomplished with one or a combination of the basic Elements, and all potions made in the Natural Magick tradition take into account the Elemental powers of each ingredient.
The Air element is the principle of wind, speech, thought, ideas, self-discipline, and joy, and Air oil or incense could be used to magickally evoke any of these powers, or to mark the Eastern corner of a Temple. The Fire element is the principle of heat, passion, activity, work, and desire, so Fire oil or incense could be used for any of these types of workings, or to summon the Southern Watchtower. The Water element is the principle of emotions, psychism, compassion, peace, healing, and dreams in the West, and Earth element is the principle of physicality, wealth, growth, grounding, mysteries, and secrets of the North. The Spirit element is the principle of connection, magick, change, transformation and Divinity, and is seen as existing as the Center of the magick Circle, as the Circle itself, and as the Multiverse beyond the Sacred Circle.
Elemental oils and incenses are often used in a ritual setting is for the calling of the Four (or Five) Directions, Guardians, Watchtowers, or however they are called in your tradition. The oils can be used to anoint candles which mark each of the directions, or the incense can be burned to emphasize each direction as it it summoned.