As we've found out yesterday, OS X 10.8 Mountain Lion is going to be released to the public today.
This year I've decided to take a slightly more relaxed approach — e.g. I don't plan on doing a clean reinstall — but certain steps should always be taken before a major OS update. So here's what I did:
Check if the apps that I use on a daily basis are Mountain Lion compatible. This can be easily done using the site RoaringApps.
Backup my user data with Time Machine. This works pretty fast in my case, because I do TM backups on my Mac mini's secondary internal drive.
Clone my Mac mini's primary HDD with SuperDuper!, twice. I have one backup that goes to a FW800 HDD, usually updated daily and a secondary backup on a USB2.0 HDD that I won't touch until I'm fairly certain that 10.8 works fine. Of course, I checked the integrity of both backups, by booting from them.
That's it. Mountain Lion can come.