Having SEO friendly website navigation basically means that every page of your site can be crawled by a search engine. Search engines start at the home page and then look to see how many clicks a user will have to click to get to any certain page. The farther (more clicks) a sub page is from the home page the less weight the search engine gives it.
This is one reason why sitemaps are useful. You should create a sitemap that has a link to every page in your site. Then create a link to the sitemap on the home page. This way, every page in your site is only 2 clicks away from the home page.
You should also link to the most important pages of your site directly from the home page.
Note: When I say “link to” I mean have a static html link like this:
<a href=”/mainsubpage.html”>Link to subpage</a>
You should link some of the content of your home page to inner pages of the site. This makes a more natural linking flow and the more natural you appear to search engines the better.
Taking the intro paragraph we wrote for the dry cleaning site I will show you how adding links to the content would appear:
Are you looking for a guide to starting a dry cleaning business? You’ve come to the right place. We will teach you why dry cleaning franchises are becoming one of the most popular and most profitable business ventures to start. There is a reason that the phrase “being taken to the cleaners” was adopted into American society, because there is money to be made in the dry cleaners business.
Those links would go to the appropriate sub pages of your website. Multiple links can go to the same sub page, because you also want to point your users in the right direction.