When designing a theme in PS, use different layers for different WP elements (e.g logo, page, featured_blog, featured, homecontent, footer, header etc)
Flow: design mockup -> transform to HTML -> add WP functionality
To show the boxes you can temporarily use a 1px red border
Quote: Finally because our <div> element has position:relative, we can now use absolute positioning inside and set right:0px for the menu and it will be aligned to the right. This is great for a WordPress theme because as the person creates new pages the menu will extend, and this way it will stay right aligned.