I was consistently scoring a 20 in bootcamp and got a 24 on the actual PAT. For TFE, you have to analyze the crap out of the answer key when you are done with the test. Meticulously look at one perspective and mentally figure out what a line, diamond, circle etc converts to in the other perspective. Most questions have trends i.e. The lines in one perspective don't correspond to the correct spatial position of the other perspective. A diamond = three lines and the answer has two lines, so the it must b a circle or square. Realize how a solid line on the border of one perspective affects the other perspective.
If you do this enough, you will eventually "see" the object. Once you can do this, they are very doable. Achiever tests 1-3 has a TFE answer key that has all three perspective and a 3D image for ALL the answer choices (both right and wrong answers). This is helpful, but I think Achiever sucks besides this. I would keep going with bootcamp and just mentally pour through the answers. You will develop a mind for the common things that differentiate answers.
