For WordPress Website optimization you should take a look at: https://codex.wordpress.org/WordPress_Optimization
I took a look at your pagespeed report and the main thing there are the images you are using. There are many plugins that can optimize them for you. I like this one in particular: https://wordpress.org/plugins/imsanity/
As per the server cache, you can either try the popular cache plugins or ask a sysadmin to optimize these options for you on the server level.
In my case. Using Apache 2.4 I have this configuration in my pre_virtualhost_global.conf:
# Cache Control Settings for one hour cache
Header set Cache-Control "max-age=3600, public"
Header set Cache-Control "max-age=3600, public, must-revalidate"
Header set Cache-Control "max-age=3600, must-revalidate"
# Mod Deflate performs data compression
BrowserMatch ^Mozilla/4 gzip-only-text/html
BrowserMatch ^Mozilla/4.0 no-gzip
BrowserMatch bMSIE no-gzip
Pagespeed also offer instructions on the other factors. You should follow them.