I am scheduled to take the broad field science Praxis II in June.
At least it's less information than Social Studies (which is everything from the beginning of time on including history, geography, civics, psychology, etc etc)...lol.
I did take the middle school science test, though, and all I can say is you're doing what I did. I got textbooks and went through all of my science classes' notes (I was still in college).
Best of luck! What is the passing score for your state? The way most scores are, the range is 100-200, so if the passing score is 150, that's only 50% you need to make on it.