i self studyied all cpl and atpl exams on my own, i recomend you do human factors then aerdynamics then general knowledge. as for met, air law, nav, and performance they all come easy with experience when you are flying around getting hrs. as you will use what you learn out of these subjects pretty much everytime you fly. also with the casa exams they take practice in learning what the question is asking you it is never a straight forward question.