Clean Up your Browser. We usually spend a lot of time online and guess what...? Your browser keeps track of all of it. That can be a big list of junk for Safari or Firefox to remember. How often do you go to your history anyway. With “tabs” enabled, very recent history is almost redundant, so let’s purge it. Under History in Safari, go to the bottom and click Clear History.
Still poky? Look under Safari and click Empty Cache. Don't click Reset Safari or you'll lose everything you've saved. use that only as a last resort...
Get a Larger Hard Drive. When your hard drive reaches 90% capacity you’ll notice a slow down in performance on all levels. The operating system uses hard drive space for a good number of temp files. Many applications require hard drive space to do their thing. If you don’t want to upgrade the internal drive at least consider an external hard drive. Once attached, you can off-load files you don’t use often, especially images like your digital camera pics.
Clear the Clutter off your desktop. Does your desktop look like the picture above? This is like coming home from the grocery store and leaving all your groceries on the floor. Leaving files on your desktop is a great way to bog down your operating system.