I’ve always felt it was a hassle to gather the data needed for tuning mysql, let alone interpret it. Here’s a great tool to do just that: the MySQL Performance Tuning Primer Script. From the page:
Currently it handles recomendations for the following:
Slow Query Log Max Connections Worker Threads Key Buffer Query Cache Sort Buffer Joins Temp Tables Table (Open & Definition) Cache Table Locking Table Scans (read_buffer) Innodb Status