I pretty much stuck to the final sketch. I tried drawing large tentacled beasties, but none of it was working for me, so I tried for the terror within.
The original plan was to create it with Corel Painter, but it was acting dodgy. A victim of my finally upgrading to OS X Snow Leopard? I won't be upgrading to Lion anytime soon. To their credit, Corel customer support quickly supplied fixes, but I had wasted enough time as it is, so I went back to pencils.
I had meant to leave the top part of her face out, as I think the focal point of this piece is pretty obvious, but after I bought a frame, I found a lot of leftover space, so I added the rest of her face. There's at least three references I used for that, but mostly from my puny mind.
Then I got to work on the tentacles, which was really fun for some reason, probably because they weren't based too much on reality and so I couldn't screw them up too much. After they were done, I had to go over the rest with darker pencils so that the tentacles didn't stand out THAT much.
I'm really happy with how this turned out. I wish I had more hours in the day for this. Oh for a pile of money or a rent-free living situation.