The Top Five SEO Mistakes According to Google Webspam Head Matt Cutts.
(1) Not having a website or having a website that is not crawlable is the biggest mistake he sees.
(2) Not including the right words on the page. The example Matt gave is: don’t just write, “Mt. Everest Height” but write, “How high is Mt. Everest?” because that is how people search.
(3) Don’t think about link building, think about compelling content and marketing.
(4) Don’t forget to think about the title and description of your most important pages.
(5) Not using webmaster resources and learning about how Google works and what SEO is about.
Stolen from: http://searchengineland.com/the-top-five-seo-mistakes-according-to-googles-matt-cutts-157574
