I wouldnt pay too much attention to that searchengineguide site as it seems they use blog spam to get their site in the SEs - not the best example to teach with
http://www.google.com/intl/en/webmasters/seo.html is a real good page from Google explaining the pitfalls of using most SEO approaches - including those that call themselves SEOs to try to get your money
http://www.google.com/intl/en/webmasters/ is the overall Google page for webmasters and contains some good info - other than that, there are at least 3 people on this board that will be glad to answer any questions you have about SEs with good information for free