1. Hard Drive Space
You should keep a minimum of 10% of your Hard Drive free to ensure smooth running of your machine, I normally aim for 15-20% free, so I still have a bit of space to play with
If you are unsure of whats exactly is taking up your hard drive then you can use a utility like DaisyDisk (Available on the Mac App Store) to track down those space hogs.
2. Clear Your Desktop
Lots of people use their Desktop as the store for all their files, this increases the amount of time it takes to startup as all of the preview icons need to load, so by storing these files elsewhere in the filesystem then you will improve startup times
3. Disable Login Items
Lots of items starting at login will also slow down your machine, and often, these will continue to run in the background, taking up memory and utilising the processor unnecessarily, to prevent this, do the following
Open System Preferences
Click on Users & Groups
Click on your account in the window on the left
Click on the Login Items tab to the right
Click on the items you no longer wish to run at startup, such as iTunes helper, VM Fusion helper and click on the minus button at the bottom of the window to remove them.
4. Disable Dashboard
I haven’t used Dashboard since 10.4, so I tend to disable it, you can do this by opening a Terminal window and typing the following
defaults write com.apple.dashboard mcx-disabled -boolean YES
This will fully disable Dashboard so you will not even be able to run it manually by clicking on the icon in /Applications, to re-enable it if you change your mind then you can do type the following into a Terminal window
defaults write com.apple.dashboard mcx-disabled -boolean NO
5. Repair Permissions
I recommend repairing permissions after every software update, but most people don’t have time to do get round to this as well, until the machine becomes slow and unresponsive.
To do this, navigate to /Applications/Utilities
Open Disk Utility
Click on your startup volume (Usually named Macintosh HD)
Click on the First Aid tab and click on Repair Permissions at the bottom of the screen
6. Repair Disk
Sometimes disks will develop directory structure corruption over time, this isn’t a problem if dealt with promptly, but in the worst cases will need attention from a specialist application such as diskwarrior.
To check if your drive needs this doing you can run a verify disk from Disk Utility, as follows
Open Disk Utility (from /Applications/Utilities)
click on your startup volume
click on the First Aid tab and click on Verify Disk
If all is well you will receive a green message signalling the drive is fine
If its not then you will recieve a red message stating the cause of the error
To run a repair disk you will need to boot from a non system drive, such as a Mac OS X Installation Disk, or a home made Bootable USB
Once you have booted from one of those then you will need to run Disk Utility again, and this time click on your startup volume and choose First Aid, then click on Repair Disk.
This may need running more than once, although my recent experiences have shown that it will keep running until it has resolved the issues.
Finally I use OnyX to clear out a few caches and log files, I’d recommend sticking with the default options with this app, a free download from Titanium Software, just make sure you download the version that matches your Operating System, if you are unsure which OS you are running then you can find out by clicking on the Apple Icon in the top left corner of the screen and clicking on About This Mac
8. Add more RAM
Put as much RAM as you can afford into your mac, I’d recommend the minimum on the following Operating Systems
10.4 (Tiger) – 1GB
10.5 (Leopard) – 2GB
10.6 (Snow Leopard) – 2GB
10.7 (Lion) – 4GB
A lot of people hardly ever reboot their macs, and for some unknown reason are even strongly against doing this, even though the majority of the time a reboot fixes a lot of issues, I’d always choose this option on a slow running mac, in case there are some applications that have been closed but refuse to release the RAM for the OS to reuse