I only use Macs occasionally, so when it comes to doing upkeep, I'm nowhere near as up-to-date on which file system nooks and crannies to clean out when I need to reclaim drive space. If, like me, you're prone to doing this sort of surgical space-freeing, it's good to know what files to delete... as well as those you should keep away from.
As this article over on GigaOm points out, the best way to get an idea of what's consuming all your drive space is to get your hands on a file visualiser. The guide recommends DaisyDisk, but that will set you back $10.49. Instead you can grab the less pretty, but very functional and free Disk Inventory X, which we've recommended before.
Once you file the visualiser up, the first thing you'll likely spot is the "Sleep Memory Cache". This is the equivalent of Windows' "hiber.sys" file and is responsible for storing your machine's memory whenever it's put to sleep. It'll be massive, but it's not something you should delete.
You'll also want to keep away from the "~/Library/Mobile Documents/" as nuking files here can also see them vanish from iCloud.
These are just a few of the recommendations from the GigaOm guide; if you're looking to do some OS X spring cleaning, it's one to check out.