High results Google PageSpeed Insight with a WordPress Theme

How do you develop a WordPress theme with a high score in Google PageSpeed Insight ?

 1. Download : http://html5blank.com/

 2. Install a cache plugin (e.g. WP Fastest Cache).

 3. Optimize the loading of JavaScript (e.g. Autoptimize & WP Deferred JavaScript).

From this point, you have a foundation on which to further develop your theme.
An example can be found at : http://blankwp.utilewebsites.nl/

Want to have a theme developed with a high score or want to optimize your old theme ?