It seems like a hard test to prepare for. Really, I think that the best preparation is a good, generalist program in English literature. Like, taking a broad range of classes. There's also a bit of luck involved, in that if you're a Romanticist and there's a lot of Romanticism questions, then you're golden. If not, it's harder to get a good grade.
I didn't prepare at all, but took the test in the same year that I took Medieval, Romanticism, Theory, 19th-c. American, and Shakespeare grad courses and I got a 75th percentile, which isn't great or anything, but it's better than my 59th percentile the first time I took it after studying and flash carding, but being out of undergrad for four years. YMMV.
There's also some strategy involved, in that you should try to get to the end of the booklet, answering all the questions that you're sure of. I also used the strategy of running through that first round by only answering the questions with short- to medium-length passages to read. I then went back to the beginning and spent the rest of the time considering as many other questions as I could, and I left any answer blank that I couldn't narrow down to 2-3 potentially correct answers, because of the penalty for wrong answers. I think I left like 30 or 40 blank.