It is generally believed that in order to create a well-balanced perfume using essential oils, it should contain 3 notes:
A TOP NOTE: Such as lemon or basil essential oil to give it a fresh, light quality that is instantly noticeable due to their fast evaporation rate.
A MIDDLE NOTE: Like Geranium or lavender essential oil usually makes up the most of the blend and is the scent which is noticed a while after first impression.
A BASE NOTE: Such as Jasmine or Patchouli essential oil is the rich, heavy note which emerges slowly and lingers. It also acts as a fixative to prevent the lighter notes evaporating too quickly.
Happy blending!