This is coming from a College Student. I've taken NYS Earth Science regents. Been there, done that. :] This is not coming from someone who's never taken it. That being said, here's some advice:
* Study any old tests you have, they will have a lot of info that will likely be on the regents test.
* Look over any of your notes. Lots of valuable info there, too.
* Ask your teacher for help in studying for it or see if there will be an after-school session covering the topics on it.
* Have a study-group with a couple friends a few nights before the regents.
BEST OF LUCK. :]