I have recently been drawing on note cards. And I have heard that some really talented writers use the method of writing a sentence on a note card (or sticky note) as a way to keep trucking on through a difficult scene. And story-boarding has been a technique in the television/movie/video game business for quite some time. So what's the craze with all these little blank squares?
Well, for one, they aren't really that intimidating. They're not infinite capacity (like a Word document) and they're not larger than your head. You don't have to feel like you're going to succumb to madness if you tell yourself that all you have to finish is writing the next sentence, drawing the next panel, or making the next study flash card for your social psychology class. They are just bite-sized enough that you can get them done in a limited amount of time, and easily carried on the go.
Besides these benefits, I think the appeal of note cards or sticky notes is just the fact that you can rearrange them. Drawing from my own experience, I find that editing a paper makes me really nervous if I don't make little annotations in between sentences such as "EDIT!" or "USE DIFFERENT WORD" or "WRITE TOPIC SENTENCE, DANGIT!" I have come to the conclusion that it is less my own madness and more the fact that when a paper is written out on a computer screen, it looks complete. Done. Presto. There's absolutely no more work that has to be done on it. Right?
I think that generalizing the usefulness of note cards and sticky notes can be really helpful. Even if you are not literally sitting down with a bunch of 3x5" cards and proceeding to draw your next masterpiece, you can use the same logic. How about writing a sentence per day in a notebook so that you can get to your ultimate writing goal? Or drawing a picture section by section (or stage by stage: contour, color, shading, background)? Taking small pieces can make a really great whole. And you won't be freaked out by the monolithic "done-ness" of a particular thing - it's always easily editable, easily moved around, and never set in stone.
Give the note card thing a try and see if you like it, and be sure to leave a comment about what you think of doing things in small chunks!