"Oh my, how colorful!" should not be a persons first reaction to your page. Every color on a page should have a very good reason. You should be able to count the number of non-unique colors on one hand in most cases. Many people have this strange outlook on programming; "It is there, I will use it." Just because you have 65,535 colors (216 colors, if you are Netscapically Correct) at your disposal does not mean you should use all of them.
You should note my use of non-unique colors. I refer to colors in a number of ways. When I refer to a color by name it includes variations of that color. If I am refering to a specific color then I will refer to it by the hexadecimal (#RRGGBB) value. Sorry if the hex values are a pain. I studied digital electronics in college, hex is burned into my brain forever ; ).
Ex:
This is some blue text.
This is some blue text.
This is some blue (#0000FF) text.I scrutinized six sites on the web. These sites were USA Today, CNN, Washington Post, MSNBC, Microsoft, and Huntington Bank. The number of non-unique colors per page averaged out to be about four. I did not include any advertising in the color survey, because I doubt they have control over the ad department. These sites are designed by very talented (and well paid) web authors.
You should not randomly choose colors. Be very precise when choosing which color are used. A good example of bad coloring would be Stanford University. Stanford's web site sports the color scheme of a rival college, according to Vincent Flanders. You should not switch colors in the middle of the page, either.
You must have relatively high contrast between foreground (text) and background colors. You must, also, be sure to set all page colors. Leaving one color unset can be disastrous. Especially if the viewer has adjusted the default page colors in his/her browser. I suggest the following color scheme: <body bgcolor=#ffffff text=#000080 vlink=#2d2d2d alink=#000000 link=#000000> This renders a page with a white background, Navy-Blue text, and Black links with Grayish visited links. This scheme has very good contrast. It portrays a professional and attractive look, as well.