Unique content is King. Search engines love new, unique and updated content. If you produce new content at a rate of just one reasonably sized page per day and tied in with the other advice throughout the site, I can almost guarantee you will get good listings. Remember though, write for the visitors but cater for the search engines. If your field of expertise fits into a niche in the market, all the better for you but you must get unique content all you will fall behind.
Visitor Navigation. This is more an aesthetic feature of your website focused at real visitors but you need to have some sort of standard navigation that is the same throughout your whole site. People can be put off and leave your website if they find it difficult to browse easily, search engine bots may also miss links if they can only be found deep within your site. Try to make as many internal links as possible available on each page.
Site Hierarchy. Site hierachy can be great for adding keyword density to your web site. An example of site hierachy working effectively would be this page, seo-advice.php. The full link contains SEO seo-advice.php which is very beneficial in the way search engines determine your sites relevance to a particular subject. Use your domain, folders and file names to your advantage.
Avoid Blackhat SEO. Blackhat SEO is a vast topic that commands little respect from real webmasters as it means using underhand methods to gain search engine rankings, although the site is usually banned quickly. Blackhat SEO includes using link farms, search engine spamming, hidden or disguised text, fake meta tag data, using duplicate content and using doorway pages. I would recommend you stay away from tactics like this as you will end up losing out in the long run.
Targeted Linkswaps. Link swaps are great but you must make them work for you. It does little good for you when your going for top search engine positions when your link swaps are untargeted. You should choose some specific keywords for both the link text and the link title text then make sure before you link swap that the other webmaster adds those specific keywords with the link.