There are general guidelines for optimizing a web page, every webmaster needs to know.
META Tags.
Descriptions, in meta tags, play an important role in all true search engines. They do not play any part in PPC or directories. Be sure to know how to write well-defined descriptions, regardless of which search engine you choose to promote your web site.
The other name and http-equiv Meta data elements have specific uses. If the Meta data is a name element, it applies to the client/viewer process. If the Meta data is an http-equiv element, it applies to the HTTP/Gateway/Protocols process or HTTP header information.
Dublin Core.
The Dublin Core elements are for indexing through another means which doesn't help with the standard search engine. It's a specialized set of definitions. If you're on the networks that use that information, you'll know it. If not, don't use it.
Other uses.
There are elements of Meta data specifically used to assist in Assistive Technologies. There are elements used to help handicapped persons utilize the Web. Search engines do not give these elements any useful weight. Don't expect them to help you in indexing your site better.
General guidelines for what not to do.
Do not use comment tags of any fashion in your page. That's wasted document weight. It is not used, by most search engines, in any fashion. When a search engines does use it, it is not enough to overcome the punishment you receive from those who don't. In fact, some consider comment tags as spam.
Don't use a section in your page, providing a list of keywords/phrases, at the bottom of the web page. Do not use ALT and TITLE attributes as a dumping ground for keywords.
If the attributes, and comment sections, are used as dumping grounds, the site becomes burdened with useless information for the most important purchaser on the web - the disabled person. You want a site to be used by everyone! Do not forget about the visually-impaired.
Conclusion.
While there are many approaches to optimizing a web page, these are general guidelines to follow to get you started.