If your foundation is too light:
Use it as a highlighter: For a nonshimmery take on a highlighter, apply your light-toned foundation to the middle of the nose to elongate, on the upper cheeks to add brightness, or on the top of the Cupid’s bow to lend definition.
Save it for another season: Skin can lighten and darken depending on season, so use that to your advantage. When well blended, a lighter foundation shade in the Winter might just match your complexion perfectly. Still off? Apply it with a wet sponge to blur its paleness.
Recognize the power of powder: If the shade is only slightly too light, then still wear it as normal, but consider layering a darker powder on top. Or just add a bit of bronzer as a finishing step, targeting the cheeks, nose, forehead, and chin.