Before you go outdoors apply a sunscreen that has a sun protection factor (SPF) of at least 15 or above, with a broad spectrum of protection against both ultraviolet A and ultraviolet B rays. I'd stick to brand names for quality, and choose a scent that won't make you think twice about using it - it only works if you use it!
Lotions, creams, and sprays with a SPF of 45 is all the sunscreen that your skin needs; higher numbers are only useful under very extreme conditions.