This video was recently published on the Google Webmaster Tools blog. It's a great insight for small businesses or those new to SEO about some of the common strategic mistakes made by website owners.
The video concludes with 6 tips which I find most useful since they highlight Google's thinking behind their latest ranking approaches. The 6 tips are:
Do something cool
Include relevant keywords in copy
Be smart about site architecture
Sign up for email forwarding in webmaster tools
Attract buzz and natural links, +1s, follows
Stay fresh and relevant (social media sites, accessible on new devices)
Points 2, 3 & 4 are generally the easy part these days, they are well document across the web (including on SmartInsights) so easy to learn / follow and most popular content management systems will aid you in this area. Points 1, 5 & 6 however are not so easy and while processes exist, it is down to you to think of a "cool" idea, publish enough relevant and "cool" content to attract "buzz" and help you stay relevant. Two recent blog posts from Danyl Bosomworth explore further the points above, though from a marketing viewpoint, not just SEO.