Page and Site Content

Relevant and optimised content is the keystone to successful search engine optimisation and is the one main area you should concentrate on.

While "Content is King" is usually followed these days by "but Links are Queen" there is still truth in the adage, interesting and original content can still get you links and is what searchers and search engines both look for and prefer.

Site Content

Commercial sites can have particular problems with content as quite often they overly focus on themselves with little if any coverage of the wider picture.
Add to that a general reluctance to link to outside sites and a fondness for corporate "fluff" and they either don't turn up in search results or become overly dependent on outside links to do so.

Even if the content is limited ab initio I'd strongly recommend building a site structure that lends itself to the addition of future material, consider as wide a focus as is feasible and to add at least one new page per month.

Page Content

Optimising page content is ensuring the page has a good title, page specific meta tags, external files for CSS/javascript and copy that "appeals" to both humans and search engines.

I don't bother too much with keyword density, though if I'm targeting a particular phrase I try to ensure it appears both "whole" and in its constituent parts, so "search engine optimisation" might appear as "page optimisation can greatly help in search engine rankings" kind of thing.

Some people believe changing page content regularly keeps things "fresh" and helps rankings, I'm a bit sceptical about this and have pages ranking that have been untouched in years, so unless a change substantially improves the page, I wouldn't bother doing this.

For further reading on content I recommend: