I cannot comment of the 4-5 day courses.
In preparing students for the exams, i have a suite of mock exams and like others my main approach is to get them to a) understand the question, b) understands why the correct answer is correct and c) understand why the incorrect answers are incorrect.
If there any weaknesses then we use the books and the references to remedy them.
The people i feel sorriest for are non native English speakers, for whom the unnecessarily complicated sentences can prove difficult.