The Google, she's a fickle ... search engine. Much like a woman, just when you think you're really understanding her, she changes her mind. An optimized website requires a deep understanding of current algorithms to get the engine running and subsequent constant care. Think of it as "remembering your website's anniversary." And hell hath no fury like a website scorned.
Like any other communications/marketing project, optimizing your website for search engines begins with analysis -- of not only your current website, but your competitors. An important piece of this research: Asking customers, "What words would you use to search for our business on the Internet?"
Further develop keywords and phrases from the initial analysis and benchmark the current status of the website. From this position, clearly measurable objectives can be determined from which your success can be gaged.
Content & Submission
Only after thorough analysis and research do you begin creating the meta titles, description tags, making sure to use one to three keyword phrases per page. Submitting your URL to website directories like Yahoo!, Business.com and DMoz helps gain traction.
You can't do all this just once and assume you can sail along for the next three years ... Effective SEO takes continuous testing and analyisis and well as maintenance. A professional in SEO knows when search engines morph their methodology and ensure your company stays ahead of the curve.