Much of this seems to rest on good, old common sense once you have a very clear idea of exactly what audience your site wants to attract and target. Much can be puzzled out by understanding the basics of how search engines work (always under debate) as they 'serve up' the results of whatever key words a user types in for a web search. Some interesting reading in this area includes:
There are automated analyses that can be easily done on-line to provide your choice of quick or in-depth reports about how your current page set-up will rank relative to what you're already using in your MetsTags. This is a great jumping-off point in determining whether further "professional help" is required, and/or whether only some minor tweaking is warranted.
If you haven't yet, you'll soon be hearing a lot about this hot new area called SEO and all its various "tools" to help get your web site to show up "in the top 10" search engine results. There are a lot of subtlties to it and a lot of "tricks of the trade" that can be employed. But no matter how you cut it, there are only 10 places in "the top 10" and it seems like everybody is expecting to be put there.
Contact an SEO expert for additional information and direction.