Always use phrases, not plain words, in your list. Frame Sites using frames should definitely make use of tags. The main HTML file contains the tags, but fails to provide robots with any real useful information about the Web site. Therefore, you should utilize the description tag to provide a description summarizing the site's contents. Some search engines even give precedence to text near the top of a Web page, so make sure you place the most important stuff at the top.
Some search engines consider header text particularly important.
If your site mainly consists of images, you should use the ALT attribute to describe each image. Most search engines index the ALT attribute in the tag. The overuse and repetition of keywords may result in a lower relevancy score and possible omission from some search engines. Most search engines count only the first few occurrences of a keyword or phrase, and some even penalize you for repeating words to improve your site's ranking. Infoseek and Lycos are two search engines that penalize sites that are suspected of repeating keywords, and Altavista will disallow URL submissions from those who spam the index.