Spend time with as many examples as you can. Also, this may sound bizarre, but try visualizing things in the real world different. Imagine what the room you're sitting in would look like if it were a mirror image. What if you were sitting on the other side of the room? What if it was upside down? You want to practice flipping stuff all over the place in your mind. The better you can manipulate and visualize images in your mind, the better you'll be.
The angle ranking was pretty brutal. Although I wouldn't recommend the book for much else, the Barron's DAT book has some really tough angles that are very close. The morning of the DAT, I woke up and went through all those angles a couple more times. This seemed to work pretty well, even though the resolutions on the Sylvan center computers was funkified.
Also, I put this in another thread in the pre-dental section, but it's been suggested that visually intense 3D video games can help. Use this advice at your discretion, though - don't get too sucked in.
I've been a gamer since I was a kid and the visualizations in the PAT section always came easily to me.
The bottom line is - practice like crazy. Practice every day. Nothing will replace practice. Even though other people will say that the tests you see in Kaplan or TopScore are easier than the real PAT, they're far better than nothing.