Undoubtedly there are some brand new Mac users out there that just got their first Mac as a holiday gift. If you were to ask me "Hey Terry as a new Mac user, what should I know?"
Here are the 1st 3 things I would tell you:
1) If your new Mac is a portable Mac like a MacBook, the 1st thing I would do is setup the security to require a password upon startup/wake from sleep. Although Mac OS X has you setup a Password for your new account, it logs you into that account automatically every time you boot up. This is probably fine for most desktop Macs at home, however if your Mac is stolen, the thief would also be able to log in automatically. This makes all of your data and identity that much easier to access. Turn off the auto login to at least make them work a little harder.
2) Get an external drive and backup via Time Machine. If you want to take things up a notch, partition that New External drive using Disk Utility and use one partition to backup to with Time Machine and the other partition to do a SuperDuper! bootable clone to. This way if your drive ever crashes you would not only be able to restore to a new drive via Time Machine, but you would also be able to boot up immediately from the other partiton and immediately be productive. This is crucial if you use your MacBook for presentations as it could take hours to restore from a Time Machine backup and the show must go on.
3) Join your local Mac Users Group. Users Groups are a great resource to learn about your new Mac. As a new Mac user you will find that most users groups out there will go out of their way to help you when you're stuck! Find your local group here.
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