For your website to be successful two things matter the most:-

1. People find your site and
2. They find what thay are looking for in your site.

SEO is all about increasing the visibility of your site so that people can find you easily on searching in search engine, directories, networking sites and therefore for the first part of be successful, you may need to employ SEO techniques among other web marketing techniques….

As for the 2nd part, what do you do to make it easy for visitors to find information within your website?

There are a few ways to make your website user friendly and accessible :-

Site search:

This is useful when you have a lot of products and information, and visitors want to access the information instantly. If your website does not have a site search, have it included in your layout, it is easy to do. If you have a word press theme, you may want to check out the below-mentioned link for information on how to install site search in your site.

http://wordpress.org/extend/plugins/custom-site-search/

This article also provides a lot of useful information on installing site search:-

http://searchenginewatch.com/article/2066283/Search-Engine-Software-For-Your-Web-Site/

Below is a site search example:-

Sitemap:

Sitemap provides the site layout, and in many cases describes what a particular page contains. Almost always, the products and information given in the sitemap are linked. It becomes easy to access any information. Below is an example of a sitemap:-

Breadcrumbs:

Breadcrumbs are very useful if your website has several levels. For instance a shopping site, or a directory such as Dmoz, in such sites if you do not provide breadcrumbs your visitors will get lost. For a small site having breadcrumbs may not be that essential. An example of breadcrumb navigation is given below-

SEO and website navigation are closely linked together. Let me explain.

Whenever a visitor types in a keyword or key term in your site search box, they are leaving some very valuable information for you. On analyzing the search keywords, you may find that sometimes visitors do not find what they are looking for. If the search term is relevant, you may want to optimize your pages better so that the relevant pages show up when a keyword is typed in. This is where you can use on-site SEO to optimize your website’s content.

Sitemaps can be made extremely information rich so that not only does it do a good job of directing visitors to the information they want to access, but also the sitemap can be the page from where the search engines can pick up all the links from. It is recommended that you create a html sitemap map, if you want to have the layout in an image that is okay too, provided you provide a html version as well.This will make it easy for search robots to access all the links in the site. Through breadcrumbs you can see the category, the product, and key term displayed. This is an excellent example of using SEO and navigation to optimize a website’s accesibility.