I've been building websites for many years now and one thing I've learned is that poor construction of a website can destroy the best laid SEO plan. No matter how good your content is, if you don't have an advanced web design with modern HTML elements, your site can wallow on page 15 of Google.
Advanced Web Design is more than just graphic design and content writing. It involves programming elements like HTML5, CSS3 and JQuery scripts, all combined carefully so as not to conflict with each other and be compatible with all browsers. Most sites today are Content Managed, like Wordpress or Joomla. This gives web developers the unique opportunity to start with a fully operational, advanced web design, with SEO tools built in to the dirty work of META generation and Sitemap creation for search engines to index. They also come with a dizzying array of templates both paid and free to customize to their customer's specs. Here is where it gets tricky.
SEO used to be you insert some keywords into your text and META tags and presto! You're at the top of Google. Because so many people out there took advantage of the early SEO rules, with Affiliate Sites and other garbage, Google had no choice but to evolve it's Search Algorithm. This has become a complex formula that Google stays vague about, but suffice to say it can tell the difference between a site that is relevant, and one that isn't. As an SEO expert, it's important to keep up with the Google Webmaster Guidelines, and make sure you know how to write content.
But more than that, the right template choice can make or break your SEO. Search engines now look at many other things besides content, such as article header titles, paragraph structure, page layout and even HTML elements like DIV statements over TABLES. The Navigation (menus) of your site must be structured well, with easy to follow links not based on deliberate SEO, but that help the reader get relevant information about the subject matter. If you think about it from the point of view of the person searching, it makes more and more sense to create your website in a clear, easy to read format that delivers the reader to your conversion pages, such as contact us, buy now, or click here.
The load speed of your site is also very important, as most people won't wait more than a few seconds for your page to load; neither will search engines. If your site contains things like large images, banner affiliate ads and other database calls that slow load time, you will wind up on page 10. Hosting is a factor, but you can speed up any website with little things like page caching, CSS and Java compressions and other tricks to decrease load times. Check out http://gtmetrix.com/ and see how your site performs. Anything above a 'C' is acceptable, so don't panic too much.
There are more and more templates that come with these tools built in, so choose carefully when picking a base template. Learn CSS and how to use it, as it is the best way to change typography and styles within your site; and decreases load time as well. The Framework of the template is also critical, so try to use technology like the Warp 6 Framework from YooTheme. Google especially likes this framework, and other engines all copy Google, or even directly use their engine!
Don't overtake your site with flash or other fancy effects, as they are invisible to search engines, and annoying to humans. Use slideshows that are actual HTML, so engines can see them; but it also gives you more freedom to change slide content later if you use text with style. Give the reader what they are looking for quickly, and with as little "bells and whistles" as possible.