Make a CD with all of your favorite songs. Then while your studying, you can play the music IN THE BACKGROUND and it might help you concentrate more because something you like is playing. Thats what I do, except I put it on my laptop and then I get distracted because I keep changing the songs. So make a cd. it might work! :D

What grade are you in? That matters especially with what grades you get. In high school you have to try all the time, not just when you want a cell phone or something. I'm only in grade 9, but I listen to my brother when he lectures me about High School. ._.

Tennis: Don't assume. I make that mistake allllllllll the time. In swimming class, I thought we weren't getting evaluated for our time swims, so I was lazying around that class. Thats when I realized that the "substitute" instructor we had in that day was an evaluator. T_T I still ended up passing my bronze medallion though. :D

Congrats to your sister!