Meta Tags

When I use the meta tags to fill in keywords, should I only fill in all the keywords (for all subject areas) on my main or homepage, and should I only fill in keywords related to the subject category on the subpages, or should I just use all the keywords in the meta tag (for the all subjects on the site) on all its pages? This is confusing me. I would, off course, like to have a good position on the search engines, but also prefer to stick to the rules and not to spam with keywords.

Have your meta tags reflect what is actually on the page and not use all the keywords for the site on each page. Pay more attention to the title of each page as the title has more of an impact on your search engine position than the meta tags on some search engines.