Pianorak
I found the met exam one of the hardest. Also, it was the subject I least understood, despite reading and re-reading.
I don't want to frighten you, but, for me, the met exam was the one which was least like anything explained by Thom or like the examples from the Confuser.
There were two questions which I had never seen before, and several others were phrased somewhat differently.
I was able to answer about 14 of the 20 questions, without too much trouble, but I had to spend a lot of time over the other six. For some, of them I just worked on eliminating the obvious wrong answers, and picked the most probable from what was left, and crossed my fingers.
Strangely, I only failed the form 214 example question, which was a completely new example. When the instructor tried to explain why the answer was area one not two, I said his explanation would apply to either area, and he agreed - so it does seem it is not straight forward.
In the end, my preparation was to be sure I could answer all the questions in the Confuser, and then hope for the best.
I wish you the best of luck with it - however, once you've passed it don't just forget about it - try to use your knowledge, and other's experience to fly safely. And keep reading - it eventually begins to make some sense.
GB