Usually a slow WordPress site is caused by a bad plugin, cahing (Where you can get the biggest benefit for the smallest hassle, according to WordPress),  and server optimization.

I did some digging on the WordPress codex and came across some information on optimization, and read through their optimization cheat sheet, and tried some of their recommend plugins like WP-Cache2 and WP Super Cache.

The above options might work for you,  if  you are willing to spend some time going through the documentation and figuring it all out. I do recommend installing a good cache plugin, it has worked for me in the past, however here is a quick and dirty option to optimize at the Database level.

I’ll try and make easy for those of you who have none or little experience with phpMyAdmin.
*I recommend backing up your database first!

1. Log into your  Control Panel (You can necessary url’s/info  from your host provider)
2. Go to your Databases, find the Database you want, then click the phpMyAdmin link (or login to phpMyAdmin via whatever information your provider has sent you)
3. Once in phpMyAdmin  click on the database name (in this example the DB is called wordpress)




4. Use the checkbox to check off which table you wish to optimize (Or scroll
   down and click the Check All link if you want to optimize  your entire
   Database)
5. From the With Selected pull-down menu, select Optimize Tables




6. That’s it,  take your site for a test run and hope for the best!