Their are 2 basic fragrance types from which all others derive: citrus and herbacious. The overall composition is made of 3 parts or chords - top, heart, and base. As with music each chord is made up of individual notes. We then decide which fragrance notes best illustrate the concept (eg Lavender, Vanilla, Bergamot etc). This can be quite intuitive but is also governed by which notes blend well or contrast with one another.
The success of a fragrance is judged on how the composition plays itself out on the wearer's skin. Each note will evaporate at a different rate, starting with the fleeting top notes, opening up to the heart notes and finally revealling the long lasting base notes. The final formulation is then matured and aged for a minimum of 8 weeks to allow the components to settle and blend smoothly with each other. It is only then that the success of the fragrance can be judged and final adjustments made.