how to increase website speed

I m using w3 total cache and it works fine for me. Got 91 Google pagespeed rating. What matters is simply use a single program or plugin for a single task for example, if I wanted to optimize my image for faster loading I would check speed with jetpack or other plugins at a time but not together(eww image plugin works great for my site), reduce javasript, css code flow, minimize them(you can do it at w3 plugin itself). One more thing, if you are using cdn service; check the settings over there if the same has been activated in the dashboard settings. Hope for your good speed, G'luck