In the past, I've learned the hard way about the importance of backing up my work. After accidentally saving low resolution files right over high resolution files and various other incidents that ended in lost work, I became practically religious about saving my work in several places.
Because I work digitally, it's especially important that I keep my work saved in a several different places. So, for example, if something horrible befalls my hard drive, I can still access my work elsewhere and thus save my business as well as my sanity.
So whether you're a graphic designer, an illustrator or a fine artist, I recommend getting in the habit of backing your work up. Yes, even if you're an artist who works with traditional media, you still need to develop the habit of scanning or photographing your work and storing it digitally!
My first line of defense is saving my work in several different files as I progress. I usually save a new file at about three or four different stages of my illustration process in Photoshop. This ensures that if I goof and save over a high res file with a low res or something else similarly goofy, it won't be a total loss because I can go back to a previous file and start again from there.
My second line of defense is saving my work on multiple hard drives here in my studio. As I'm working, naturally I'm saving my files to the hard drive on my computer but at the end of each day I also copy everything I've been working on over to two different external hard drives, including one that is portable. Portable hard drives are fairly small, about the size of a passport but about half an inch thick or less. I drag my portable hard drive with me whenever I'm going to be travelling or just away from my house for a few days. It gives me peace of mind knowing that all my hard work is tucked away in my bag.
External hard drives in general now, whether portable or not, are fairly cheap now so if you don't own one now, I highly recommend that you invest in one. In additon to backing up my work on mine, I also back up my photos and other things that I don't want to lose.
And finally, when it comes to backing up my work, I couldn't function without my Dropbox account. Dropbox is a file sharing service that I love for various reasons:
* You can use your Dropbox as offsite storage for photos, work, etc.
* You can use Dropbox to easily sync items between multiple computers. So if I'm working on my desktop and want to work on my laptop instead, I just drop the file in the Dropbox folder on my desktop, then the file is waiting for me in the Dropbox folder on my laptop.
* Dropbox also makes it easy to share a folder with someone else, which makes it perfect for collaborations!
* And you can also use Dropbox to deliver files to clients, uploading a zip file and then sending a download link to your client.
If you're just starting out, you can sign up for a free account with 2GB of storage space or you can choose a plan with a monthly fee to get up to 100GB of storage space. I can't say enough good things about it, Dropbox has really made my life quite a bit easier!
So that's it, my method of keeping my work from getting lost in the cosmos: saving several different versions of each illustration as I progress, backing up on two external storage devices in my studio, and backing up again using my offsite storage at Dropbox.