Now that you're sure you're using the right formulas and the correct amount, which order should we be applying them in? "Always go from the lightest weight and viscosity to the heaviest," Kilner says. "Water-based products should be applied first (most toners/serums) and end with oil-based products (many creams/foundation)." And if you're already following this rule, perhaps take your time with your routine, allowing each product to absorb and dry before applying the next. "If you like to use multiple products and steps in your regime, then it can also work to spread out your regime a little further," she says. "If you do other tasks such as brushing your teeth or blow-drying your hair between layers it will make sure the skin has enough time to absorb the products fully and still allow you to have the best of everything!"