Skin care is also important.  There is no magic regime that works for everyone.  You must take your individual skin type and the climate you're living in, into account.  Basically, before you put on any kind of makeup, your skin should be clean and strong.  You will also need to protect your skin from the sun and weather while you're wearing makeup.  If your foundation doesn't have it already included, you should wear sunscreen under it.
 

Foundation and Blush

You should choose a foundation that not only matches the lightness or darkness of your skin, but its undertones as well.  When people talk about whether someone has cool or warm color, or whether they are a winter or summer color, they are talking about which range of colors works best with the person's undertones, not just how dark or light brown it is.

Here is a diagram of the color range for most darker complexioned people:

Cool colored people are those whose skin color has some bluish or reddish tint.  Neutrals have both bluish to red and golden or bronze tint.  Warms have golden and yellow tint to their skin.

It would seem rather simple to match colors for us, but you all know our skin darkness and tint changes with the seasons and with age.  So it is a good idea to buy makeup for the year in winter, and then again in summer.  It is also prudent to reassess your best colors, especially of foundation, with an experienced makeup artist every few years.  What fit you at 20 may look horrible at 30.

Here are some examples of how different colors look on different skin tones:

One of the issues many women of color have with foundation is facial hair.  Some of our ethnicities tend to grow darker, thicker sideburns, upper lip, and chin hair at puberty.  It can be very tempting to opt for trendy methods, but our grandmothers knew best when it came to this.  The best methods to preserve our skin are still threading and tweezing.  Today, there are epilators for facial hair that are basically like mechanical threaders or tweezers.  Never wax your face.  It stretches the skin beyond its natural tolerance, and breaks blood vessels.

Foundation should be applied with a moist (not wet) natural sponge or with the fingers, over the whole face including the lips.  It is better to use too little than too much, so make a few dots of it on your skin and spread it around.  If this is not enough, add a little more, until you have an even layer but not streaks.

If you accidentally use too much, gently wipe it with a clean tissue, and then spread what is left with your fingers or sponge.

A totally translucent powder should be used over or instead of foundation.  Apply this with a "kabuki" or large puffy brush.

Many women of color don't really need blush to highlight our facial contours, but if you do, then take the whole face, not just the cheeks into account.  Step back and look in the mirror.  Wherever you need highlights, be it on the cheeks, forehead, and/or the chin, give them a light brush, and blend it in.  Unless you want a stark effect, the blush should seem a part of your skin color.  Some people opt for a light glitter or shimmer powder instead of blush, because this is what actually gives the effect most women of color are looking for in a blush.