This is just one example of using black on purpose, rather than as a cop out. To offset and accent white pieces, black is lovely and crisp.
You CAN put three colors together, as this picture and several people in my office can atttest to. Just be sure they are chosen purposely and are of the same tone or mood. The orange and yellow would not work with a hunter or forest green, for example. Here, the green almosts acts as a neutral, balancing the orange stripe and yellow top.
When mixing several shades of the same color, think compliment, versus contrast. These shades of purple work together since they act in concert to compliement the skirt, which contains all of the other shades used in the rest of the outfit. The result is colorful without being loud.
I love orange. I really love orange with brown. Here, the brown and orange are so harmonious, I couldn't imagine the orange with any other neutral, except maybe tan or khaki.
Monochrome: Feel free to start with a color you love, like grass green, and continue it throughout the outfit. Note that this outfit includes a colorful top, so colorful accessories, and some neutral peices for balance.
This is one way to mix colors in different families. The yellow top is so bright that any other color used as a contrast must be equally bright, such as the earrings. Again, neutral peices complete the look.
Combining purple with red isn't as hard as you'd think. The colors are next to each other on the color wheel, making them complimentary more than contrasting. Just be sure the tone or mood of the peices work together.
This is a great way to add purple. With an aqua top and basic neutral jeans, the purple hoodie and shoes are put together without looking over the top.
Love, love, love this combo. Navy and mustard are weird in theory, but sophisticated and pulled-together in practice.
P.S. Check out http://www.polyvore.com/cgi/home for more outfits with color.