How to optimise HTML even further ?

Is there anyway to optimise HTML even further for coupon boxes, and also when I am inspecting "GrabOn" in google pagespeed (developers.google.com/speed/pagespeed/insights/?url=...), it is saying "None of the above-the-fold content on your page could be rendered without waiting for the following resources to load. Try to defer or asynchronously load blocking resources, or inline the critical portions of those resources directly in the HTML."

So ideally, if I need to inline the critical portions in the HTML itself, it will increase page size. 
what are the possible ways to increase the performance of the page?