In WordPress Dashboard, click “Performance”, “General Settings”, switch “Minify Mode” to “Manual”, “Save all settings”. Click “Minify”, “Help Wizard”. If you did not select “Manual” previously, “Help Wizard” would not show up, it is different from the “Help” button at the upper right corner, which only gives you FAQ and such. Still cannot find it? See this message “To rebuild the minify cache use the empty cache operation. Get minify hints using the help wizard. Update media query string to make existing file modifications visible to visitors with a primed cache.” in the middle of the page?
So after you click “Help Wizard”, a “Minify: Help Wizard” page pops up, just select the files you want to minify. The plugin does give a suggestion that says “Typically minification of advertiser code, analytics/statistics or any other types of tracking code is not recommended.” Since I’m using some advertiser and analytics codes, I left those untouched. Click “Apply & close”, “Empty the page cache”, “Empty the minify cache”. Next I tried PageSpeed Insights again, I did get a much better score this time.
Also, it seems like another effective way to help speed up the webpage loading is to turn off any Preloader function. With this theme Loom, if I have that feature turned on, the page won’t display till it has all its advertisements, captcha images loaded up.