How to fix/optimize pagespeed error and pingdom.com error?

How to fix/optimize pagespeed error and pingdom.com error?

1. Don’t use any optimization or cache plugin at all
2. Don’t use a lot of plugins or scripts on load time, review your themes and plugins so if anything is uselessly loading make that loading conditionally
3. Cache only media files like images, audio or video if any
4. Re-check your memory limit in config file
5. Try to re-use the images thumbnails instead of creating a lot of thumbnails of each size(s)
6. Try to divide your script in loading and posting, e.g. all of the load should not be on the server at once in both cases either you are posting a form or posts etc are loading with pagination because sidebars are taking load as well.