Speed up website?

Slowness/high CPU usage could be due to (but not limited to):
– A poor or memory intensive theme. Switch to the WordPress default theme and test loading time and see if you see a difference. If you do, may be your theme can be re-written to be more efficient.
– Poor or memory intensive plugins. One by one disable plugins and test loading time and see if you see a difference. If you do, may be that plugin can be re-written to be more efficient.
– your server is slow (e.g., “process hang”, overload, you get a lot of visitors, other problems, etc.); generally, every inexpensive host out there is slow.
– I don’t know if you use CloudFlare or not but if you do I would suggest deactivating it and seeing if it helps. Also sometimes a good purge of the cache on CloudFlare can help.
– Lots of images can cause slowness. Also images loaded without compression.
– Lots of external content (facebook/ gravatar/ google adds, etc.) and redirects in general tends to slow sites down.

Here’s a couple of links that might give you some ideas on how to better deal with this:
* https://docs.woocommerce.com/document/troubleshooting-a-slow-site/
* https://woocommerce.com/2016/03/woocommerce-speed-first-steps/

Use plugins to optmize/speed up sites. For example:
Autoptimize
WP Super Cache

Use Jetpack’s Photon option to speed up image delivery.

Also see this tutorial: http://www.wpbeginner.com/beginners-guide/speed-wordpress-save-images-optimized-web/

Ueful codex: http://codex.wordpress.org/WordPress_Optimization