If you can't find any examples in books (IQ test books normally have them) try making some yourself on bits of paper and folding them until you get a concept of which sides meet which.. May sound daft but its worth a try. If after this you're still struggling just go in and give it your best shot regardless.
I believe it is possible to increase your competency in these tests with practice. I practiced them from books for a week or so before my tests and actually found this to be the easiest section, though there was a few examples that i had not seen before.
The key in all these initial tests is not to panic. You will be put under a lot of time pressure and will not answer all the questions. The idea is accuracy, not quantity. Above all try to relax and enjoy the day, it actually is quite good fun!
Good Luck
