In the same way that your clothes need to work with your shape and personality, they also need to compliment your color, or more specifically, your complexion, which is the combined appearance of your skin tone, eye color and hair color. Have you ever noticed how Latin and Mediterranean women almost always look amazing in red and black? or how middle eastern women look far better in the deeper shades of most colors (navies, olives, maroons, etc. as opposed to blues, greens and reds)? If so, you've noticed the effect of color working well with complexion. This effect has been studied, broken down, and rebuilt into a science for more than 100 years by students of fashion and cosmetology.
Here are a couple examples. Note how Courtney Cox and Katherine Heigl look better on the left, where they are shown wearing colors that work well with their complexion. The effect is subtle but it is strong.
If until now you've chosen colors based on something you saw a friend wear, or colors you "just like," there is a good chance you look bad in them. Men notice this, even if only subconsciously. If you haven't taken the time to learn what colors make you look best, you are throwing away potential attractiveness, and therefore undercutting your chances with men. I've observed in many instances that a woman is far more radiant and attractive due to her choice of a color that magnifies her natural beauty. The effect is significant.
The best book I've found for women about color is called Color Me Confident. I bought a few different ones for men and women, and this one blew the others away (as did its counterpart for men). I like it because it uses modern celebrities as examples, does a good job of explaining the categories it uses to group complexions, and also has sections about the fit of clothes and makeup as well.
This book could reliably be your only resource. However, I have one other suggestion. Find a female celebrity that has your complexion (including eye color, which makes a lot more difference than you'd think) and spend some time looking at images of her on the internet, paying close attention to the colors she wears. Try the following: do an image search for her name and a color, and scan the results. Pay attention to how many instances there are of her in that color. Just as importantly, pay attention to what doesn't come up when you do these searches - i.e. the colors for which you cannot find many instances. Take Penelope Cruz for example. Click on each of the following image search links and notice how the results show whether or not the respective color (and what shade) works for her, based on the collection of images that appear in the search results:
Penelope Cruz Red
Tons of instances of her wearing red, and she looks smoking hot in it (Latin women...)
Penelope Cruz Blue
Plenty of instances of her wearing blue, but notice how in most it is navy rather than a lighter shade
Penelope Cruz Orange
Basically just one orange dress, and notice how it is a burnt orange rather than bright
There are also a ton of websites out there that either describe how to choose colors that work for you, or else offer online (or in-person) consultations. There are some good videos on YouTube as well. While searching for some of the pictures above I bumped into a few good blogs, which have a lot of examples of color done well, as well as explanations of the theory. Take a look:
While it should only take an hour or so to learn the principles and figure out what are your best colors, it can take much longer to implement them in your wardrobe. It won't be easy to overcome some of your misconceptions. Someone may have told you once that pink was your color (for example), and you've worn it ever since, convinced by the confidence of their compliment that it made you look good. But their statement may very well have been wrong, in part or completely - even if you thought they knew what they were talking about when it came to fashion. Maybe they just wanted to make you feel good. Treat every color (or color combination) as suspect until you know it really does work on you. Be prepared to throw some of your clothes away.
I know these things because I paid no attention to my own color for years, and my appearance suffered because of it. Sometimes I would put on a shirt and recognize that it looked good on me, but I would never know why. Frankly, I never really wondered - I was just content that it did look good. And when I finally learned about the need to address my complexion and learn what looked best on me, I started to realize why those shirts had looked good. In fact, my memory of those instances eventually served as examples in figuring out which complexion I had and what would work well with it.
So if you aren't up to speed on your color, go buy the book, do some research online, and hit the mall. Men notice, and it will make a difference.