This is summary from Bryan McQuade, Google’s developer to improve mobile pages render.

To make your mobile web page render in under one second, you should:

  • keep server backend time to generate HTML to a minimum (under 100ms)
  • avoid HTTP redirects for the main HTML resource
  • avoid loading blocking external JavaScript and CSS before the initial render
  • inline just the JavaScript and CSS needed for the initial render
  • delay or async load any JavaScript and CSS not needed for the initial render
  • keep HTML payload needed to render initial content to under 15kB compressed

Read the full article here: