Read Bob Taits IREX book 5 times, regardless of how painful, when you can understand and teach the subject to your teddy bear / monkey or little brother then the exam should be a piece of piss. Dont pay anyone to teach you, not worth it, unless your struggling and the monkey cant work out the difference between a radial and a banana. Oh and dont get too caught up on the orientation stuff in the front of the book, not a big part of the exam and will make more sense to you in the actual aircraft.....Have fun