Man,
Yes, i too found SC very difficult in the beginning!!
But now, after getting used too i save time by doing SC very fast and almost get 15/18 correct!!
this is how i did!!
I used Princeton review for SC and tried to distinguish questions explained in the 8 types in the book!!
If u need i ll give u the collection of questions too invery section............say, misplaced modifiers, tense, parallel construction,Idioms,comparision etc.,
Do concentrate much on Idioms which I feel the most tough!
All the best~!
Max!!