Something that I think makes a difference, Google and Yahoo seem to give preference to sites that have the keyword in the filename/URL. For example www.ufo-design.co.uk/graphic_design.php would be a good idea on a page about graphic design. I have seen improved results by using this structure but beware placing files inside directories that are named the same or overusing keywords in URL’s you can be sure keyword spamming comes into play and you will get penalised.
When you search for a phrase in Google look at the URL of the website link in the results. You can see it has been cached or at least appears to be so as it is in bold text.