Dreamy waves start with healthy, clean hair. Desir suggests occasionally varying the types of shampoos and conditioners you're using to ensure you reap a range of benefits (i.e. colour care, hydration, damage repair, and so on). His favourites include Living Proof's Colour Care Shampoo (£24), Restore Conditioner (£24), and Restore Repair Mask (£33), to name a few.