There are several classifications of colors (neutrals, brights, pastels) and families of colors (yellows, blues, greens... etc) as well as intensities, contrasts, and more. Hardly a one-post conversation!
Since we talked a bit about the CMB color seasons last time, I'll say that most seasons have an off-white neutral, a near-black neutral, a brown neutral and a navy. Winters have the pure white and pure black. A good priority is to find out which of the neutrals are your neutrals. Interestingly (to me at least), the brown-neutral that CMB cites for Springs (which I am) is a camel. But I've never seen a camel, in person, that looks good on me. Usually the camels that I see look good on Autumns. But one night I was watching an old movie and I saw two women come in - one was a blonde spring and the other was a redhead (autumn, albeit a delicate one). They were both wearing light camel... but the tones of the camels were different, and the blonde looked great in hers. Since the original CMB was written in the late 70s, I would guess that there were more options in the neutrals... in 2011, you're well advised to be very careful with camel if you think you are a Spring! Virtually any season can wear any color family, it's the tone that changes everything.
Middle of the road neutrals (brown/grey/soft navy) blend in and disappear. Light or dark neutrals (ivory/white/black/charcoal/chocolate) make more of an impression. All neutrals somehow look more expensive than brights and pastels, more's the pity. Neutrals are where it's at for backbone of the wardrobe clothing, which is a lesson that I'm learning quite unwillingly. (I do like my brights!) Neutrals are very good for slimming the figure. For instance, today I'm wearing an ivory linen slim skirt with an ivory peasant blouse and put over it a denim jacket when it was pick up the kids time. That made me (visually) into an ivory column, and was slimmed further by the dark blue of my jacket. A straight line from ankle to collarbone - it's a good thing. All of those neutrals made for a casually elegant outfit that I'd wear pretty much anywhere with confidence - and that's the type of outfit I aim to fill my wardrobe with.
Secondary colors in fashion aren't the same as secondary colors in art. The secondary colors in fashion are the soft colors that can sometimes be used as neutrals but which make more of a statement. Goldenrod, brick, olive, plum, cadet blue... that school. You can have a suit of that color, but it tends to be a bit much. A jacket or a skirt, either one, looks great. They blend well with neutrals, perking things up a bit without standing out. The cost of those colors is in finding the ones that work well with your coloring and the fact that they tend to be a bit trendy.
Brights are self-explanatory. This is where you find your "power colors". Mine is turquoise, my mom's is red. BFF's is coral. What's yours? They get in your face and they say HI HIHIHIHIHI. The brights are the focal points in your outfit no matter what you do. That's the point of them. Find YOUR bright colors, and work them. The downside to brights? Again, they can be very trendy. Also, unless your fabric is of highest quality, the brights soon fade - and since they're eyecatchers to begin with, you'll be remembered as having owned that particular piece of clothing. You can be the girl in the red coat (oo la la!) but know that at some point you're going to have to rotate it to storage at the very least.
Next up, a series devoted to discussion of specific color families. Pardon me while I tie one hand behind my back, I tend to get a wee bit over enthused when talking about color... :D