The main things all major search engines look for when evaluating your Web site are content and links from external Web sites. Thus, you can increase your search engine ranking by developing keyword-rich content that is of value to your visitors and other Web sites. Techniques that fail to offer better content for your visitors or try to “trick the system” can get your Web site banned from the big search engines.
When it comes to search engines, words are most important. Search engine Web crawlers look at your words on your Web pages, not your images. So, as you write the content for your Web site, remember:
You might also consider creating Web pages with valuable content that other Web sites will want to link to. Informational or instructional content loaded with keywords can be part of your linking strategy.
Finally, when you design your Web pages, remember that Web crawlers cannot read graphics, but they can read alt tags. Alt tags are short text descriptions that appear when you roll your cursor over graphics. Alt tags should offer the reader more information on the image and contain keywords.