Rebuild your desktop once a month by holding down the Command and Option keys as you restart your computer. Leave the keys pressed until the computer asks if you want to rebuild the desktop. Click OK.

Remove fonts you never use. (Open the Fonts folder in the System Folder and drag the fonts out.)

Open the Extensions Manager control panel and turn off system extensions you don't need. For example, if you're not on a, visit- http://komhard..com/2009/06/how-to-increase-speed-of-macintosh.html