Visual Web Design

The combination of colors you choose to use on your site is essential to its visual appeal. An unpleasing or awkward mix of colors not only looks bad, it can distract users and reflect poorly on the credibility of the site.

A great colour scheme can help you to achieve the the highest quality look and feel when applied to your header, footer, navigation, body, and text.

The following from 1stwebdesigner lists 10 basic visual web design mistakes:

1. Bad Font Usage
2. No Images, Text Only - while having enough white space is important, there needs to be an adequate balance of your use of images and text throughout.
3. No Paragraph On Long Articles
4. Very Tiny Font Size
5. Heavy Flash Usage - too much can slow down your website
6. Body Text Above Colorful Background - It's never a good idea to attempt placing text (any color) over a colorful background.
7. Too Many Advertisements
8. Unwanted Pop Ups - This is a quick and easy way to lose visitors.
9. Too Long Articles
10. Link Colors Aren't Visible - Your link text colors should be a different color from your regular body text. An example would be a bright blue link in contrast to the black text.

http://www.1stwebdesigner.com/design/basic-visual-web-design-mistakes/