Enhancing Page Load Times

I’ve been working all day trying to fix my page load times. So far I’ve gotten a pretty good score, but there’s one section left that I can’t seem to fix. It’s the static content cache. I’m trying to create Far Future Expirations, but it doesn’t see to work. I’m using a plugin to do this called WP Far Future Expiration. What am I not doing?

This is the site I’ve been using that will show my results for the static content. https://www.webpagetest.org/performance_optimization.php?test=131120_T4_1AM0&run=1&cached=0