A lot of times, a person who desires to dress a certain way that expresses their personality is going to end up mixing light and dark colors on the palette of their outfit. And while it can most definitely look interesting when you have black mixed in with bright colors, it can also be done very badly (consider a goth version of Rainbow Bright). So when you combine lights and darks, keep in mind that very often in life, discretion is the better part of valor. If the combination is done badly, you are not going to find it very easy to be taken seriously by anyone.
For instance, if you wear your darker colors lower on your body, you are going to be perceived as taller and more effectively constructed than you would if you attempted to wear light colors below and dark colors (especially black) up top. The effect can almost make you look as if you are crushed into the floor, which is only good if you are very tall and you do not want to show that off. The colors that you wear are forces which you are using to your advantage. But they are only going to stay advantageous to you as long as you wear them properly, with respect to what they are.
You are also not going to want to combine your dark colors and your light ones in a nearly 50/50 mix. Just like what would happen if you were to combine cool colors and warm colors in a nearly equal (or even completely equal) mix, the effect is devastatingly dull. Thre is no emotional resonance when your outfit is too carefully matched like that. You almost seem to disappear when you try to combine your color scheme into such an evenly matched grouping. So make sure that one type is dominant and the other is submissive.