Try to incorporate singular and plural cases of words, as well as active and passive verbs. Also make sure your keyword list includes both general and specific words related to your site. You rarely want to target a single keyword, because, with the billions of words indexed on the Web now, one word simply won't cut it. Always use phrases, not plain words, in your list. 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. Don't repeat same keywords more than 3 times. All rights reserved.