You might think more is more when it comes to moisturiser, but Martin says that's not the case when you've got a big event and you're going to be sweating. Opt for serums that pack a punch of hydration without the thick layers of moisturiser. Martin recommends Kheils Ultra Facial Moisturiser (£24.50) as it's lightweight, hydrating, and provides just the right amount of slip (but not too much) before makeup application.