New answers tagged my.cnf
You changed the innodb_log_file_size and, as you are not using 5.6 (where that is handled automatically), you have to delete manually ib_logfile0 and ib_logfile1 when MySQL is stopped for InnoDB to recreate them with the new size on start. Make sure you do a clean shutdown before doing all that, not a crash / innodb_fast_shutdown = 2.
Try MySQL Tuner which will give industry standard recommendations. The link for getting started with mysqltuner is: http://www.faqforge.com/linux/optimize-mysql-performance-with-mysqltuner/ You can download mysql tuner from here http://mysqltuner.com/
Top 50 recent answers are included