It's not too early to start thinking about getting your Mac prepared for Mountain Lion. By the way, I'm going on record as saying that Mountain Lion will be released to the public on July 18, 2012 -- if history repeats itself, Apple will hold its third-quarter financial call on July 17th and announce the availability of Mountain Lion for the next day. [Well, that didn't quite happen -- but don't be surprised if it's still the day after the earnings call, now scheduled for 7/24. ?Ed.]

One of the best ways to ensure a smooth transition to Mountain Lion is to make sure that you've cleaned your Mac. I'm not talking about washing and detailing your favorite Mac; instead, I mean getting rid of the junk files that accumulate from the first day that you pull a Mac out of a box and start using it.

First, it's a good idea to check your current disk usage to make sure that you'll have enough storage to perform the upgrade. Select Apple menu > About This Mac and then click the More Info button. This launches the System Information app. Click the Storage tab and you'll see detailed information about what's taking up space on all attached drives:

Expect Mountain Lion to take up about 8 to 10 GB of free space. If your drive is low on space, it's time to clean up. Free apps like Grand Perspective and Omni Disk Sweeper can tell you what big files are chewing up space, giving you an idea of what to delete. However, use caution! Don't delete files just because they're big. When in doubt, Google file names you don't recognize, and take special care removing files from your Mac's Library folders.

Also think about emptying the Trash. Some new Mac users don't realize that they have to empty it occasionally,