A couple handy scripts to help tune MySQL
https://answers.launchpad.net/mysql-tuning-primer/+question/166577https://launchpad.net/mysqltuner
https://answers.launchpad.net/mysql-tuning-primer/+question/166577
Update: not worth using these as the actually end being self-defeating. They use the very same resources that they suggest modifying and can skew the results. Apparently, tuning your db should be more about configuring your db for your purposes.
http://dba.stackexchange.com/questions/45551/how-to-optimize-table-cache