(Navigation) gives us confidence in the people who built it. Every moment we’re in a Web site, we’re keeping a mental running tally: “Do these guys know what they’re doing?” It’s one of the main factors we use in deciding whether to bail out and deciding whether to ever come back. Clear, well-thought-out navigation is one of the best opportunities a site has to create a good impression. | Don’t Make Me Think by Steve Krug

To design a good navigation put:

Make the navigation always visible.

With the exception of landing pages (especially a Sales page).

These Public notes are also an exception. The purpose is to create a mental flow.