Keep a note of the following points when designing a web site:
1. Frames: Avoid frames. Though search engines have limited ability to crawl framesets, they have the following disadvantages:
1.1 Not all search engines have the ability to crawl and index pages using framesets.
1.2 Google discourages using frames, and as per Google frames tend to cause problems with search engines. If you use frames, use NOFRAMES tag to include no frames version of the content. Don't just write "This page requires frames compatible browser, your browser does not support frames".
1.3 Even when search engines crawl and index frames, it may so happen that a page appearing in search results may just be one frame of a frameset, and the visitor may be taken to a bare page without header and navigation buttons.
1.4 Conceptually, a html page consists of only one frame. When using multiple frames, it essentially mean using multiple html pages within one page. This is against the basic concept of a web page.
2.1 Avoid excessive graphics or graphic images that take long time to load.
2.2 Use a feature called anti-aliasing to smoothen the borders of any text or image that you develop.
2.3 Always use alternate text field when using a graphic. This will allow a description to be displayed on the browser screen even if the graphic display is turned off in the browser. Alternate text is also helpful for search engines in identifying the content.
3. Theme: Use a consistent theme for your web site. It includes layout, and design. As this is a very subjective matter, it differs from person to person. Try to use colors, fonts, styles that complement one another. From search engine point of view, avoid excessive formatting. It is not recommended to have HTML tags outweigh your actual content.
4. Flash: This has been discussed in another page. Check out Flash advantages and disadvantages.
5. Meta tags: Always use Title, Description, and Keywords meta tags. Use other meta tags as per the requirement. From Google search engine point of view, Title and Description meta tags are very important.
6. Avoid redirects. Search engines may interpret redirect as Spam. The reason being, that a redirected page is seen by the search engine but not by an individual browsing the site. If at all you need to redirect a page, use permanently 301 redirect. A less preferred option is to use a script with at least 6 seconds of delay in forwarding the visitor to the new destination.
7. Keep the web page within 50-80 KB, so the there won't be noticeable delay in loading of the web page. If the page has content that takes more time, consider splitting the page into two or more pages. This preferred from search engines point of view as well. If the content is too long, it is likely that some portion of the page is not indexed by search engines.
8. Use of scripts: Use scripts only if necessary. It is recommended not to load a web page with too much of script as this is likely to confuse the search engines. Client side scripting relieves the server from script processing, and loads the page faster.
9. Use H1, H2 tags to identify your content headlines.
10. Validate your web pages after composing.