how to rectify google's pagespeed recommendations

Hi

Recently I upgrade WordPress default theme 2012 to 2015 for my website.

I did a google pagespeed test. For mobile it is 71 over 100 with recommendations to improve the pagespeed of my website http: hu-techconsulting.com

For desktop the page speed is 89 over 100 with recommendations from google to further improve the pagespeed.

Look forward to your help and support to further improve the mobile and desktop speed of my website please.

Thanks and regards.

benjchan