The way I first learned how to do keyhole problems was by: Picking one side, then compressing it flat down. Now see if any of the choices matches. Then pick another side and compress that one flat down. An see if it matches an answer. Makes sure you do all the sides even top and bottom, just to make sure.
Another way is to envision the shadow that each side would give off.
Eventually after doing numerous problems you will be able to do these problems like second nature. You'll be able to envision each side and compress all of them in a second.
I say that keyholes, cubes, holepunching, are the easier sections. You should not miss any questions on cubes and only take about 7minutes. You should not miss more than 1-3 each for keyholes and holepunching. Both sections should take no longer than 10 mins each. The harder sections are topfrontend, and angles. These sections will eat up your time but remember 15min max for topfrontend, and no more than 7min for angles.
PAT is just practice, and when I say practice I mean every single problem you can get your hands on. Don't get frustrated, at first you won't be able to see the answer, but in time you will be like Neo in the Matrix.