I have set up cloudflare CDN. But THis CDN has not help my site regarding site speed. I also noticed that cloudflare CDN is not detected on Gtmetrix. Does my site has problem? Problems in CDN settings? or cloudflare isn not suitable for my site.
Gtmetrix comparisin: before CDN vs after CDN
Cloudflare Free version only gives you CSS and JS compression and provide CDN only for CSS and JS, Cloudflare free plan only provide little improvement if you need more improvement get the pro version.
Completely false. The basic CDN is available to all plan levels, including caching of all assets up to 512MB each (if enabled via Page Rule, but needs to be thought about for HTML in case of dynamic content, with the Cache Everything rule). The differences between plan levels (especially Pro which adds WAF as the main headlining feature) are others and the frequency of cache evictions in case of unused resources.
The suggestions are valid, but Rocket Loader needs to be checked since changing the order code executes on the page can change the behavior of some components.