Air law is a thoroughly stupid exam, examined via a system of multiple choice questions where the answers all sound similar, which is made all the more difficult by being padded out with loads of un-necessary crap. However, whilst two-thirds of the content is twaddle, one third is mission-critical info which can (and will) save your life.
The only way through that I found worked for me, was to buy the Oxford Aviation Academy interactive discs, and then sweating through exam after exam, until I got up to a reliable 85-90%.
It's a total fag, but you just have to get through it. The alternative is to spend a day with Derek Davidson, where you will get drilled full of info all day long, culminating in an exam (which you WILL pass).
Be careful not to use up too many of your 'lives' on the exam - you get three go's at it, and then you will have to sit a specially asigned exam at CAA headquarters, which is not a good thing. Good luck!