The online hazard test practice sessions are a godsend. It's not that it's difficult to sort out where the emerging potentially dangerous situations are, but you need to teach yourself how to respond to the system to register your awareness at the correct time. (I spent quite some time clicking too early to register it properly, which counts as missing the question!) The answers to the theory test are not terribly difficult, if you just study up a bit.
Like Margo, I took maybe 12-ish hours of lessons here. I've been driving since 1972 in the USA, but the rules are just enough different here that I really needed the lessons. (Plus, sitting on the wrong side of the car while driving was just...weird!)
I would definitely recommend lessons from a certified instructor who can coach you as to what you need to do to pass.