MySQLTuner

If you have one or more MySQL installations, it's a very good idea to check your configuration settings using some best practice checks.

The MySQLTuner script assesses your MySQL installation and then outputs suggestions for increasing your server’s performance and stability.

Installation is a breeze;

Download the script:
wget http://mysqltuner.com/mysqltuner.pl
Make it executable:
chmod +x mysqltuner.pl
The run it, you'll be prompted for your mysql password;
./mysqltuner.pl
It will return output similar to this;
snip output

At the bottom you'll see the recommendations for your installation, try them, let them run for a while then rerun the tool.
Enjoy!