To keep your skin hydrated, moisturizer is the best solution; it keeps the skin hydrated and lock in all the other layers of the products you already applied. Morning moisturizers are lightweight that contains SPF 30 or higher.
Retinoids are getting popular nowadays; they help reduce dark spots and breakouts. But they might be irritating in some cases, for people with sensitive skin as an example or if they have been used in daylight. That’s why retinoids should be applied at night.
Face oils should be applied after you finish with all your skin care products, since oils are thick and nothing can penetrate them.