This post provides an excellent summary of what is required for a small business website: SEO Checklist for Local Small Business Websites
If you’ve been thinking SEO is arcane and complex, the emphasis on simple and clear business thinking is really worth noting. A site put together using this approach makes sense to people – and without too much effort, will work very well for search engines.
An item I would add to the list would be this: include a blog in your website, and use it to share information about the problems that matter to your customers. If you post regularly to your blog in this way, your small business website is likely to get an increasing flow of organic search traffic.