I'll give you a very brief outline of the steps suggested to give your Mac a tune-up, more for my future reference than anything, but I highly suggest you go read the full article.
Free Up Disk Space
- Clear out any old/unused files (.dmg, .pkg, etc.) you should have at least 3 times the free space on your hard-drive as you have memory installed. If you have 4GB of memory, you should have at least 12GB of free space on your drive. (In the Windows world we generally recommend at least 10% of your drive space free, this would work quite well on a Mac as well)
- Clear out your caches and rebuild the disk directory. The quickest and easiest way to do this is to reboot your Mac while holding down the shift key, until you get to the desktop/login screen, then do a normal reboot.
- Remove unnecessary StartUp items and browser plug-ins. I won't go in to the details about this here, head on over to the original article to learn more about how to do this, if you don't already know how.
- Install more RAM. This has long been a mantra in the IT world.