I do a lot of random sketching that I never know what to do with; I like showing people my artwork, but they seem too incomplete to really push out to the world. In a sense, they're perfect little things to show off here, in my wacky space-background website.
Recently, I've been spending some time working on faces and heads -- I don't consider that to be a weak point of mine, but I also never really learned the fundamentals, which meant that I really only got good at drawing heads at particular angles. (Straight ahead, or 3/4, or profile, basically. Upward and downward tilts of the head were not ideal.)
So I've been practicing that!
For these, I followed this tutorial about visualizing faces as basic shapes. If anything, I think the main insight I gained was that the brow line is roughly equidistant to the bottom of the nose as the bottom of the nose is to the chin (of course, with some variation).