Speeding up WordPress Blogs
The more plugins you use, the slower your WordPress blog will load. The key is to use only the plugins that give you the most benefit while not taking a considerable amount of resources or load on your server. To find out which plugins are taking the most load, install a plugin called Query Monitor. It will tell you which plugins are taking the longest to load. Perhaps the slowest-loading plugin is something you don’t really need. If so, you can uninstall it. After I use Query Monitor to check my plugins, I disable it without uninstalling it for Query Monitor itself will slow down your WordPress site.
I also found a cool tip from http://www.geckoandfly.com/7512/7-methods-to-reduce-wordpress-cpu-usage-without-upgrading-web-hosting-plan about removing meta information from images before uploading them. I use a WordPress plugin called Smush to reduce the file size of image files I upload.