How you construct your URLs can also make a large difference in your site's success. Specifically some URLs may prevent your site from even being indexed. So it is important that you implement search engine friendly URLs. Since this has been covered in depth in the article linked to it will not be repeated here.
Additionally you will want to create effective URLs with meaningful identifiers and delimited keywords, that topic is covered in this article.
If your site is larger than 10-20 pages you may also want to consider creating a sitemap that links to the major sections of your site. This is not really a tool to increase your ranking, what it does do is increase the likelihood of a search engine spider finding all the pages on your site. It increases the overall interconnectedness of your site and also helps spread around, but not increase, PageRank, as discussed below.
Alternatively you can help the search engines find all your pages by creating a Sitemaps Protocol XML file, more on that can be found here.
PageRank (PR) is a major portion of Google's algorithm and similar systems are used by other major search engines. This article will not present an introduction to PageRank, but rather it will discuss how to optimize your site to make the most of what you have. For an introduction to PR please see our article: Link Popularity and PageRank.
There are two sides to taking advantage of link popularity and PageRank. The most obvious avenue that people pursue to increase their scores in these two areas is to seek links from other websites. However, equally as important is the optimizing of your own site to ensure that whatever PR you do get from other sites doesn't go to waste. In fact, due to the nature of how most site's are laid out, almost half of all the weight your home page has could be from other pages on your site. Those other pages on your site, your articles, your subsections, your product pages if you have an ecommerce site, will in many cases get almost all their PR from internal site links. Thus, your internal site structure can make or break your search engine success.
There are two issues you need to be concerned with in regards to your internal site links. The first, and most evident issue, is that internal site links are conduits for PR to travel to your sub-pages from your index page and vice versa. The second issue is that the benefit that any single page receives from an incoming link is highly dependent on the context of that link - specifically the anchor text (text used within the link itself) for the link. The issue of context has been addressed above in the discussion on building a useful menu so now I will cover the first issue.