Web design sins are generally the product of lack of experience. While designing a site there are some special points to be taken into consideration, if they are not considered then it will turn out to be a deadly sin from web design point of view.
These points are as explained
1. Typographic rules should be considered in web design.
2. For navigation one should not be much creative, it should be as simpler as possible.
3. One should not create cluttered navigation system
4. It should be kept in mind that there are certain technologies to be used to design a site.
5. Web designing should be done in a way that it binds people visiting the site.
6. Web standard should be considered before starting to design a site. If these are ignored the site will be a part of deadly sin.
7. While web designing search engine strategy should also be considered so that search engines can easily crawl a site.
8. Site should be relevant to the organization. It should have genuine and right structural information about the organization. All the content should be enriched with true information.
9. In web design the background color plays a crucial role in visibility of that site. The color should be so selected that it soothes the customers.
10. Do not skip the feasibility study.