I barely studied at all for the PAT. I just did a few practice problems so I knew what to anticipate on the test. I feel like you either get the ablility to do the PAT right away or you don't get it at all. I barely practiced that part and I ended up doing really well. I know others, though, that practiced those like crazy and didnt do as well. It probably really depends on your natural abilities. I would recommend understanding how to do the PATs, but focusing your time on other material.
As far as quantitative is concerned, I reviewed my triginometry, and used some of the methods recomended by others in this forum such as writting down a chart of sin, cos, etc with values during the "tutorial" part of the test. Also know those triangles that always come up in these types of tests such as the 3,4,5 triangle, etc. Other than that, most of the problems are logic-type, and you cant possibly study every type of logic-problem. I felt like I probably over studied for the qauntitative part. After finishing the test I realized the key is to not spend too much time on any problem that you don't get right away, because you will run out of time. Just mark the ones you don't know and go back later.
I did better on the reading section than any other part of the test, and I studied less for it than any other part of the test. I honestly did no preperation what-so-ever for the reading section. All I can recomend is to read alot of books. Also, I didnt use kaplans silly method of marking each paragraph and main-points and all that BS. The test is on a freakin computer . What are you gonna do, break out an overhead marker and mark up the computer screen? It would take way too much time to mark things down on a piece of paper. What worked for me, was to read each question and very quickly scan through the article till I found the answer. Fortunately I read very quickly, so I dunno if this will work for you.
These are just my suggestions, though, so take them with a grain of salt. I'm sure that every single person here is different, and they used different methods to be successful on the DATs. The one thing I think everyone can agree on, though, is that you need to practice alot before you take the test. Only by practicing will you realize how YOU best take the test and what areas you need to focus on when you are studying.