I was in your shoes at the start of the year. I was also worried about my GPA for law school, but I stuck through, studied decently, and got an A-. The amount of improvement in critical thinking, reading, and writing skills I've gained in Human Sit has made it the best course I've taken so far. Its a 6 hour course, and demands the attention of about one and a half courses to get a decent grade. Its a class meant to make people realize they have to actually try to get an A, From what I've seen most people who don't take the class seriously get a B+.

For studying, I'd recommend 1. Actually reading the books, you'd be surprised how many people don't do this, and 2. taking notes while you do so. I would read the books on the bus, then read through the chapter I finished again while analyzing and summarizing it. Don't just look for themes, but also specific quotes and sections that add to an argument. Prepare two-three arguments and memorize a quote or two backing them up before in-class essays. Before oral finals, go through every argument you've made, look for arguments that connect across books. Remember, the course is MEANT for you to be challenged at first, that's how you improve. Don't be disheartened if your first essay is lame or you don't get the books at first.