Well I'm having a problem in high school, and half my grades are slipping below the "A" belt, and one is on the borderline of a "C".

I can't seem to really master the topics, and I want some tips on how to study. How do you guys study, prepare for tests, and overall do your best in classes. Have any tips in memorization?
Thank you 
I used to be a straight-A student in a very competitive high school. Following eighth grade I started Wicca and felt SO enlightened... I've had a bit of a rough year (at least, the roughest so far) with a few deaths sprinkled here and there and some of my mental issues, of course.. but Wicca helped an incredible amount.
Then I started taking some time off from Wicca just because of a hectic schedule and BAM!
my grades dropped to F's, D's and C's. That's ULTIMATE EPIC FAIL for me. And it hit me like a brick, man.
I'm still trying to get my grades back up... I completely lost the entire structure of trust I had with my parents, my teachers... but believe you me, I'm working on it, and Wicca's helping.

Spirituality is a great way to handle stress, etc. in high school.