Middle school is when we start to find out who we really are. We aren't treated like babies anymore; we are expected to make our own decisions that will affect our future. We aren't allowed to be adults either because we don't have enough experience. Everyone is figuring "it" out--together.
To a lot of people, having the best classes and grades is more important than anything. A part of these people love to study, and this is their passion. To the majority left, they just want to stay on par with their friends. They are sacrificing what's left of their childhood holed up in their rooms with a textbook.
Sixth grade: You might not think this advice applies to you, but it does. A lot is expected of you as you move up to middle school - you have to manage your time between school and extracurricular activities with seven classes to think about! As an eighth grader myself, I remember how scary the thought of middle school was to me. You guys are doing great, though.
Seventh grade: Life is pretty good, right? It may seem like high school is far off, but it's only two years away. This is the year when you improve your work ethic to get as much work done in the least amount of time. Find out what you like, and the kind of people who have the same goals as you.
Eighth grade: It seems like life is just rushing toward us, not waiting for our approval. Applications, high school class choices, extracurriculars, it's all moving too fast. As you move up to high school and college, you will have the freedom to choose your classes. Some students will choose to take all the highest classes possible, but they won't choose the subjects that they are passionate about. Don't be that kind of student. Find a happy balance between what you want to do and what you can do to be the best student you can be.