We recommend some following plugins:
– WP Fastest Cache plugin to cache the site.
– EWWW Image Optimizer plugin to reduce image sizes.
– Autoptimize Autoptimize makes optimizing your site really easy. It can aggregate, minify and cache scripts and styles, injects CSS in the page head by default but can also inline critical CSS and defer the aggregated full CSS, moves and defers scripts to the footer and minifies HTML