Ah,
My favorite subject - not - I'll have you know. What is the point of studying a pointless useless chart that unless you are going be fly for the British Antartic survey (yea right, lots of them too).
Well, to answer your question, I did the national ATPL's earlier this year, and did not find them too dificult. My tips are:
1: Draw the thing out, and look at it to give you the answer.
2: Whan you draw it, remember in the north, the arrow pointing to N goes into the centre of the dart board, and in the south, they go away from it. Getting this wrong cocks it all up.
I'm no authority, but I'll happily help out if I can if you live near me.
Good luck
PS