Test at least three shades that look closest to your skin tone; swipe them on the side of your face, from the top of the cheek to the jawline to account for the different tones in your face. 

Check the swatches in natural light and look for the one that disappears into your skin with minimal blending. Double-check this shade on your forehead; if it works there too, you’ve got a match. 

Choose your foundation formula based on your skin type and the coverage and finish you want; the dryer your skin, the richer and more emollient your foundation should be. Oilier skin types should go for hydrating and oil-free foundations.