Have great content
Nothing helps your google rank more than having content or offering a service people are interested in. If your web site is better than the competition and solves a real need you will naturally generate more traffic and inbound links.
Keep your content fresh
Use friendly url's that contain keywords
Good: http://cars.com/products/cars/ford/focus/
Bad: http://cars.com/p?id=1232
Make sure the page title is relevant and well constructed
For example: Buy A House In France :. Property Purchasing in France
Use a domain name that describes your site
Good: http://cars.com/
Bad: http://somerandomunrelateddomainname.com/
Example
Type car into Google, out of the top 5 links all 4 have car in the domain: http://www.google.co.uk/search?q=car
Make it accessible
Make sure people can read your content. This includes a variety of different audiences
People with disabilities: Sight, motor, cognitive disabilities etc..
Search bots
In particular make sure search bots can read every single relevant page on your site. Quite often search bots get blocked by the use of javascript to link between pages or the use of frames / flash / silverlight. One easy way to do this is have a site map page that gives access to the whole site, dividing it into categories / sub categories etc..
Down level browsers
Submit your site map automatically
Most search engines allow you to submit a list of pages on your site including when they were last updated.
Google: https://www.google.com/webmasters/tools/docs/en/about.html
Inbound links
Generate as much buzz about your website as possible, to increase the likely hood of people linking to you. Blog / podcast about your website if appropriate. List it in online directories (if appropriate).
References
- Google Search Engine Ranking Factors, by an SEO company
- Creating a Google-friendly site: Best practices
- Wikipedia - Search engine optimization
