Electives are my bane. At first I decided to pick things that interested me, but I quickly realized that: a) they were not that interesting after all, and b) they're too much hard work (or mostly busy work), and I'd rather work on something else. So I'd end up dropping them very quickly. I now generally choose the easiest ones of those that I don't find completely uninteresting, like Cyrus said. I still do really badly in them because I'm completely unmotivated to do any of the work. For example, I'm taking a course in microecon and the final exam is in a few days, and I have no idea what's going on in that course. The only time I spent any effort on it was when I read the printed notes for a couple of hours right before the midterm (which I never picked up, so I don't know if I passed it or not, but I think I did). This will also be my plan for the final.
I'm not proud of it, but this is the way it goes... I've tried so hard to find something interesting to take, but failed miserably. Next term I'm considering taking a language (French, in which I'm already semi-proficient). We'll see how that plays out!