• Click to select a message

• Open the Colors window by pressing Command+Shift+C

• Choose your preferred color, and it will be applied to the message's background

To remove color applied to a message, choose white as a new color. You can set the background color of messages in rules (Mail > Preferences > Rules) as well.

To add extra drives to your Time Machine backup routine, do this:

• Open System Preferences from the Apple menu and click "Time Machine"
• Click "Select Disk..."
• Choose the volume you want to add to your backup routine, then click "Use Disk"
• Click "Use Both" to add the new drive to your backup schedule.

Your Mac will rotate its backup schedule to include all of the volumes you add to Time Machine, which is great because that means you can easily have separate backups at work and home simply by keeping different hard drives at each location. It's also great for automatically backing up to more than one Time Machine volume at the same location. For example, you can backup to a Time Capsule on your own network, and have a second backup on a hard drive connected directly to your Mac.

Time Machine will show you files from the volume it most recently used for backing up content. If you need to see files from a different backup location, just press the Option (Alt) key and choose "Browse Other Backup Disks..." from the Time Machine menu in the menu bar.

• Close unused document windows. If you’re not actively using an image file, close it. Each open file can take up a significant amount of memory, which can quickly lead to slow downs.

• Reduce an images resolution. Working with higher resolution images and files uses more resources. If you’re going to be saving a relatively low quality version of an image anyway, reduce the image resolution to a tolerable level to gain a nice speed boost.

• Purge history and clipboard. Edit > Purge > All. The history feature of Photoshop is useful but it takes up a lot of memory. If you’re not using it, purging the contents of history and clipboard frees up resources.

• Turn off animated zoom. Preferences > General > Animated Zoom > Uncheck.

• Turn off flick panning. Preferences > General > Enabled Flick Panning > Uncheck.

• Set drawing mode to Basic. Preferences > Performance > Graphics Processor Settings > Advanced Settings > Drawing Mode > Basic.

• Disable anti-aliasing on guides and paths. Preferences > Performance > Graphics Processor Settings > Advanced Settings > Anti-alias Guides and Paths > Uncheck.

• Adjust Photoshops memory use. Preferences > Performance > Memory Usage (adjust this based on your physical memory capacity and individual needs, a higher percentage is better).

• Turn off image previews. Preferences > File Handling > File Saving Options > Image Previews > Never Save.

• Use less Video RAM for 3D stuff. Preferences > 3D > Available VRAM for 3D > 30%, this is particularly useful for anyone using a computer with a video card that shares VRAM with primary RAM, such as some MacBook, MacBook Air, and Mac Mini models.

• Watch the efficiency indicator. At the bottom of any open Photoshop window you’ll see an “efficiency” gauge, if this falls below 100% that means you are using the scratch disk (hard drive) for memory and Photoshop will become slower. Solve this by allocating more RAM or by having less open windows.

Make sure you completely quit Photoshop and restart it and you should see a significant difference in performance.

Apparently it happens often enough for there to be an individual keyboard shortcut to instantly swap the last two typed characters, and that keyboard shortcut is Control+T.

While it may seem like a minor thing it can actually have a big impact on how fast and responsive applications are. For example, every time Adobe Photoshop, Microsoft Word or QuarkXPress starts, the application scans your fonts and builds a preview for you. After this, every time you want to change the font the application has to load these previews and display them to you, which in Microsoft Word can takes up to five seconds from the clicking the font menu until it actually displays the font list.

By disabling unnecessary fonts you can speed up applications quite significantly. As an example a quick scan of this computer shows that there are over 450 fonts installed, but typically only 20-30 are ever used. By disabling some of the extra fonts we can reduce the time applications have to spend on managing fonts.

So how do you disable fonts? You can use the application Font Book that comes with your Mac (you find it in Applications). Give it a few seconds to load your fonts then go through the list and disable the ones you don’t use by selecting Disable from the Edit menu. Damaged or duplicate fonts can also slow down your computer so while you are in Font Book select Validate Fonts from the File menu and verify that the fonts you have installed are okay. You can automatically disable duplicates by using the Look for Enabled Duplicates (or Select duplicate fonts on Snow Leopard), followed by Resolve Automatically option (or Resolve Duplicates option in the Edit menu on Snow Leopard). It is also a good idea to enable Automatic font activation in Font Book’s Preferences as it lets OS X re-enable fonts when an application needs it.

It is worth noting that the font caches themselves can become corrupted and cause slowdowns or crashes on your Mac so if you experience problems because of this it is a good idea to force OS X to rebuild the font cache. Cocktail makes this easy: open Cocktail and go to Preferences > Caches > User and select Font Caches. Next time you clear the caches Cocktail will make clear out the font caches too and force OS X to rebuild them.