Jinnie,
also make sure that you do some research before you decide which prometric center you want to go to. In my experience taking the DAT last year, certain centers had better computers/monitors that made a difference when it came to the PAT. Some centers had really old monitors that showed the angles (in the angle ranking section) as jagged lines (vs. straight lines). This made the angle ranking section really hard (when it actually should be an easier section of the PAT that you can breeze through to give you more time on the harder question types).
My suggestion would be to ask around (maybe even go visit the centers beforehand) to see which monitors are the newest. This might seem like a lot of hassle in the beginning, but believe me, it makes a *ton* of difference on your PAT score.
Also, register for the DAT earlier rather than later so you can secure a spot. Certain days at the center are busier than others. Since not all of the test-takers at the center will be starting the test at the same time (or even taking the same kind of test), people will be walking around, getting up, leaving, etc. while you are taking your test. If you are the type of person that needs the surroundings to be as quiet as possible to concentrate on the test, then you should ask the person at the testing center which days (and time of day) are the least busy at their center. They should be able to give you good advice when to schedule your DAT.
Lastly, this is one thing that I wish i knew ahead of time before taking the DAT. They don't let you wear digital watches into the testing center so if you're used to timing yourself using your watch, you should get used to taking the practice tests without your watch. Also, they only give you 3 (wood) pencils (they won't let you take in more with you) and if need another one, you need to either raise your hand so they'll bring in more for you, or go outside and get more. Same thing with scrap paper. They only allow you a certain number of pages of scrap paper at a time. So when you take the practice test, you should practice being space-efficient (but not ridiculously so) so that you don't have to keep on getting up and asking for paper etc. (which wastes time). There was one kid at the testing center who had his hand up for a *long* time and nobody came in and gave him more paper...he ended up having to leave the room a few times to get more paper and it really sapped up time.
If you have any more questions about the DAT (etc.) please let me know. I remember what it was like being on these forums last year and trying to find out as much information as possible on applications/DAT. Good luck!
~ ckow