While your standard drugstore makeup can do wonders to make you look fabulous, some things are too tough for it to handle. If you have a birthmark, you probably have trouble covering that sucker up with old-fashioned concealer. Since birthmarks can be really dark, you're going to need to pull out the big guns to cover them up. One solution is camouflage makeup, which is thicker than concealer and designed to cover up birthmarks, scars and tattoos.
Wash the birthmark well with soap and water. If it's on your face, you can use your normal facial cleanser. Just make sure the birthmark and the skin around it is nice and clean. Apply moisturizer or lotion all over the area and give it a little time to soak in.
Grab a container of camouflage makeup. This stuff is thicker than your normal concealer and completely opaque, so you can be sure you're really covering that birthmark up. Get a shade that matches your skin color exactly -- there's no fudging it when you're dealing with makeup this heavy. If you can't find a shade that matches your skin, blend two shades together until you get a close enough match.
Squirt the camouflage makeup on the back of your hand. Use your fingers to warm the makeup up. Apply it with your fingertips by patting it directly onto the birthmark. Apply a little bit at a time -- you can always add more, but if you put too much on to start then you'll need to remove it all and start from the beginning.
Blend the makeup out until it matches your skin. Once you've got an even coverage, use a translucent powder and a powder brush to seal the makeup in all day.
Reapply the makeup as needed. If you sweat or swim during the day you might need to add more camouflage makeup, even if it is labeled as waterproof.
While makeup sponges are useful for applying foundation, they absorb camouflage makeup like, well, a sponge. This makeup's on the pricey side, so you won't want to lose any in a sponge.