Holloway,
If you are anything like me I can only get so far with a book, then I have to go out and actually do it for it to actually all click together - and like you I am not thick, currently looking after a £68m project. I ended up doing a proper groundschool rather than just reading the books and trying to sit the exams and this made it MUCH easier. There are some people who can learn stuff parrot fashion just to recite it in the exams but doesnt help you in the long run.
Julian.