Step one:

Start with a white canvas. Make a new layer-set titled Clean Navigation.

In a new layer, draw a black rectangle across your canvas. This rectangle will hold your navigation links, height sized of 42px. Also draw this rectangle 25px spaces down from the top of your canvas.

Add the following layer styles: Inner Shadow.



Step two:

Create a new layer, draw a white line across the navigation space as shown below.

Set layer's opacity level to 15%.