The experiments are on Question 8 and maybe 9 and is worth a lot of marks. Some books comes with a CD with all the experiments on it. You should watch them and it might help you with the memory.
Question 9 usually has calculations. Each is worth 6 marks, even knowing the unit needed will get you half of the marks.
Question 7 is probably the hardest of the three to do well as many topics come up. Try learning the Laws of physics and definitions
Finally like Whitestar said you should practice exam questions, the book questions may not have the same language used and could confuse you.
I defo think electricity and heat are so important to revise for physics! Usually the long(er) q 8 and 9 are on electricity or experiments :) and a lot of it is calculations aswell and converting !