This is a common question. Here’s Matt Cutts, the head of Google’s Webspam team, with part of the answer…
What I can do for you:
1. Make sure your site is technically structured in such a way that helps Google and other search engines find out what your business is about.
2. Do research to find out what terms people are actually using to search for sites like yours. Note that these may not be the same words you use when you’re talking about your business, because you’re so close to the details. Sometimes it helps to have an outsider’s perspective and online keyword tools.
3. Make sure that those keywords appear, in a natural, reader-friendly and grammatically-correct way, in important places on your website, as part of the text that your readers are looking for. If your content is arranged appropriately and naturally, your site will rank for a wide range of keywords.
4. Review your content and how it is organized, and revise or rewrite as necessary to help readers better understand your message.
6. Help you with your social media presence. For example, I can get your website and Facebook working together, and advise you on how to use social media to reach people more effectively. This is where a lot of the website promotion energy is going these days.
7. If you’re blogging, I can coach you on using categories and tags, use of keywords, blog structure, WordPress plugins etc.
8. I can help you decide on whether to set up a paid marketing campaign with, for example, Google AdWords or Facebook.
I’ve been building websites for a long time and have followed the ever-changing cat-and-mouse game between web spammers and search engines. I do not engage in “black hat” techniques that could have a negative effect on your rankings. Google simply wants to be able to analyze your site and correctly discern what it’s about, so that they can dish it up to the right customers. Get that right, and you’re most of (if not all) the way there.
If you have a website, you will receive offers for SEO services on a regular basis – most of them automated. It’s not impossible that a dedicated SEO person or company could help you further beyond what I do when building a site. But it’s buyer beware. I’ve seen SEOs working from outdated or misguided theories. I’ve also talked to knowledgeable SEOs who told me what I knew already. And I certainly wouldn’t trust anyone with poor spelling and grammar, because if they mess up your website, your online image will suffer.
You might like to read the link that Matt Cutts mentioned in the video to see what Google itself has to say on the matter of Search Engine Optimization. That link leads to an SEO primer which expands on some of the points I’ve mentioned above.
See also what I wrote in 2011 about SEO. Most of it is still very relevant.