The first three don't exactly come with instruction manuals, but luckily, that last one can be understood with a little help from a dermatologist — like Beverly Hills-based doc Ava Shamban, MD . Dr. Shamban tells us that the simple step of exfoliating the skin can do a lot for your routine. "Exfoliation addresses both irregular texture from erratic cell turnover, eliminates debris and dead skin cells, and creates a smoother skin surface for better penetration of actives, more effective hydration, and an easier makeup application," she says. Nothing not to like there.