Bone up on the technical aspects the best you can in the limited time. As far as the HR questions, I think just responding to those truthfully and candidly goes farther than trying to come up with or memorize the responses you think they are looking for. People interviewing others for jobs learn to look beyond/through all the bullcrap. Don't be a robot, just be you. You aren't the person interviewing before or after you so don't try to be. They ask questions, you give answers. If you don't know something, say so. If they are your first choice, tell them that and tell them why they are your first choice, even if all the reasons pertain to your particular situation. You'll be fine.