W3 Total Cache
If you’re looking to enable WP caching, and website performance optimizations, in one fell swoop, check out W3 Total Cache. It’s a fantastic plugin that will help improve your WordPress site’s performance.
On a related note, I wrote a memo on Weightshift that covers performance tips for client websites. It’s a primer into the type of things we do for our projects, and presented in a way that’s CMS-agnostic.