WordPress has a lot of features to make a webpage more noticeable in a search engine like Google or Yahoo, such as the tags or the categories, but still doesn’t effect the Meta tags or keywords on the page that is essential for allowing these search engines to rank you accurately in their search results.
I’ve found a great plugin for WordPress to allow you to do this.It’s called Meta SEO Pack.
Once installed, in the left menu, near the bottom you’ll find an option of that name, that you can edit all the settings for the plugin.
I found the most beneficial element was that it automatically added categories and tags to the
<meta name="keywords"> element, which is what search engines want. This is particularly useful when you’ve already created a LOT of pages on your site, and haven’t had this plugin installed. Saves you on a tonne of time. I know this from experience from painfully going through a Drupal site recently and editing each of the pages Meta information.