Need help With speeding up my website?

I have some problem with my website page speed. Need to fix these:I have ran the test using Pingdom,gtmetrix, and testmysite.thinkwithgoogle
1.Caching allows a browser to store frequently requested files on the user’s device for a set period of time. When caching is enabled, subsequent page loads can be more efficient.
2.Server response time measures how long it takes to load the necessary HTML to begin rendering the page from your server. Reduce your server response time to under 200ms.
3.The following inline script blocks were found in https://deitzrefinishing.com/ between an external CSS file and another resource. To allow parallel downloading, move the inline script before the external CSS file, or after the next resource.

Inline script block #4
Inline script block #6
The following external CSS files were included after an external JavaScript file in https://deitzrefinishing.com/. To ensure CSS files are downloaded in parallel, always include external CSS before external JavaScript.

https://deitzrefinishing.com/wp-content/cache/autoptimize/css/autoptimize_c3d8f05bf1aad5a98fc0611583402c22.css
https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,regular,italic,600,600italic,700,700italic,800,800italic
https://fonts.googleapis.com/css?family=Roboto:100,100italic,200,200italic,300,300italic,400,400italic,500,500italic,600,600italic,700,700italic,800,800italic,900,900italic|Roboto+Slab:100,100italic,200,200italic,300,300italic,400,400italic,500,500italic,600,600italic,700,700italic,800,800italic,900,900italic
4.There are 2 CSS files served from fonts.googleapis.com. They should be combined into as few files as possible.
https://fonts.googleapis.com/css?family=Open+Sa ... italic,600,600italic,700,700italic,800,800italic
https://fonts.googleapis.com/css?family=Roboto: ... italic,700,700italic,800,800italic,900,900italic
5.Resources with a "?" in the URL are not cached by some proxy caching servers. Remove the query string and encode the parameters into the URL for the following resources:
https://deitzrefinishing.com/wp-content/plugins ... -awesome/fonts/fontawesome-webfont.woff2?v=4.7.0
https://deitzrefinishing.com/wp-includes/js/jquery/jquery.js?ver=1.12.4
https://deitzrefinishing.com/wp-includes/js/wp-emoji-release.min.js?ver=4.8.3
6.
6.There are 3 JavaScript files served from deitzrefinishing.com. They should be combined into as few files as possible.
https://deitzrefinishing.com/wp-content/cache/a ... /autoptimize_3e04fe801b8c78467ca4640a701be377.js
https://deitzrefinishing.com/wp-includes/js/jquery/jquery.js?ver=1.12.4
https://deitzrefinishing.com/wp-includes/js/wp-emoji-release.min.js?ver=4.8.3