Foundation is the most important part of your makeup routine, as it provides the background against which the rest of your makeup will be applied. Make sure that the foundation you choose matches your complexion, and when choosing a color, do a test patch first. If the color disappears and matches the rest of your skin, you have found a good color. But if the color stands out and looks either too dark or too light, then you need to find another color. Blending the foundation into the rest of your skin is one of the most important makeup application techniques, because you do not want to have a dramatic color change by your jawline. Be sure to apply foundation past your jawline, in order to create a smoother effect.