There is a DAT section of the forum that is worth looking through for stuff like this, but to answer your question:
Practice is the only way to learn it, and get good at it. Buy the Kaplan book just to grasp the basics, but be aware that it is extremely easy in comparison to other practice material, and in most cases it is a good bit easier than the real test as well. Crack DAT has a good PAT program from what I hear as well. Topscore is a practice test utility that is also very helpful.
I believe one forum member here also uploaded some tutorial videos for each section, and those are probably worth searching through the forum for.