I want to increse my website speed in google insights / GT Metrix, i am using best plugins such as "WP-Rocket" for optimisation and has do all the possible things for minifications. My issue is that when i Checked my performance it is asking to minify external JavaScript files such as google apis, google analytics, Facebook apis etc..
How can i implement or minify it and increase my page speed
I have tried all possible optimisations and minifying javascript and css files.
But it is asking to minify external links
If you already used WP-rockets but still google speed is not improved. Then you have to improve by eliminating unnecessary scripts and css loading in certain pages for example, if you have slider in homepage only you can remove loading js and css of slider in other pages.
for checking which js, css are loading go to waterfall after checking from gmetrix.com. Then to remove unnecessary js and css to load in unnecessary page you can you "Asset CleanUp: Page Speed Booster:" WordPress plugin which is free plugin.
If performing those also doesn't help your site speed in google it is due to your server you have to shift to better server which supports CDN.