Website optimization

Hello! I'm trying to make the site a bit faster and optimized. Google Speed ​​Insights is suggesting CSS, HTML and Javascript compression. In addition to exploiting the browser cache. I installed the Autoptimize plugin, which theoretically solves all these issues. However when I do the same, the site goes out of the air. Also note that there is no HTML that can run in the browser. Do you recommend some plugin that does this compression and that talks to this theme, that is, that when running it does not conflict and take the site off the air? Thank you, Valeska Our domain is: http://conducere.com.br