Lets see, I did the Kaplan practice problems and the Kaplan book test when I just started preparing for the DAT. Then about two months out I did the online practice DAT by the test makers. I always went back and reviewed problems I missed and tried to figure out why. Then with about two weeks left I did all three TopScore and the computer Kaplan test. I went from getting ~65 right per practice to ~80 on the the last 4, which correlated to 3 22's and a 23. On the actual test, I only ended up with a 20, but I left for break 5 minutes early because I drank too much coffee before...
As for the various sections, cube counting and hole-punch were my best sections in the practice, but the Top Score hole-punch aren't that difficult. The angle section was tough on the actual Dat, and I didn't put much time into that section in practice. Keyhole and top-front-end were a matter of familiarity. At the beginning I wasn't great on those sections, but once you do enough of them the answers start jumping out and you really know what to look for. For example, in the keyhole you start noticing the little differences between two seemingly correct answers. Finally, the folding was destroying me initially until I realized that painted sides had to fold such that they were on the outside of the figure. My basic strategy for that section was to draw the folded figure in the same orientation as the answers and then to draw the colors in myself from the flat image. Then I would see which answer matched. By the end of my studying, I was getting 14-15 right on these sections with that strategy.
The most important part of the PAT in my opinion is dealing with time. The first two sections took me about 10 minutes each, and if something was really stumping me I put an answer down and marked it. Then on angle, I just made the best judgement calls I could and really flew through the section. Hole punching came fairly naturally for me, so I was able to get through that section quickly as well. If you start with the last fold and work backwards you can get some really fast answers. I saved the most time in cube counting. I made a table of 0 1 2 3 4 5 and then on the total number of cubes for the figure. Then I counted each cube started in the front bottom row and working my way up level by level. Its important to work in an orderly fashion so you don't get lost and have to recount. Then i would make tally marks and make sure that the total cubes matched my initial total cube count. After that its just a matter of referencing your table for answers. The angle, hole punch, and cube counting typically took me 20-25 minutes, leaving me between 15 and 20 for the final, and most time consuming section as well as for reviewing marked questions. Other than the aforementioned advice on the folding, make sure on complex folds to check for shapes you see on the flat image. If the flat image has an L shaped portion, the L shape has to show up in the folded figure too. Having plenty of time allows you to draw the folded image and nail those tricky shaded side questions that are tough to visualize.
Overall, becoming familiar with the various tricks and nuances helps the most. There are only so many ways to ask those questions so you start to notice patterns and similarities. Definitely use more than one practice test type, since TopScore and Kaplan differ in difficulty. Also take advantage of the free online practice test for more repetition.