SEO stands for search engine optimization (or optimisation depending upon which side of the pond you are on) and when done properly, is nothing more than accurately communicating to the search engines what any given page is about. Granted there are ways to artificially increase the “illusion” of what a page is about but that would go against the notion of “accuracy”.
Think about what each page is about and try to find the best keyword to describe the topic of each page and use those keywords in the TITLE tag.
Again, keeping in mind what the topic of the pages are about, write an accurate description for each page, keeping all hype slogans out, save that for the “on page” copy as search engines don’t care if you think your page is the “best”, “fastest”, “newest” or “cheapest”.
While most of the search engines no longer give a rat’s ass about KEYWORDS, some still do use them so for the ones that still do make sure that you only use words that are actually on your page within the KEYWORD tag.
There are some other things you can do to help convey to the search engines what your site and pages are about such as FORMATTING and LINKING but, if you start with the above mentioned you will be well on your way to accurately communicating with the search engines.