This is a great goal. Here are some things I've tried in the past — some worked and some didn't:
Participate more in class. (Worked) It's a big self-esteem boost to share your thoughts at church and have it make a difference in another member's life. Plus, it makes you realize that you're not only there for yourself. The next time you're sitting in a class and you feel like it's dragging and you're asking yourself questions like, "Why does it even matter that I'm here?" find some way to participate. It will almost instantly change your attitude.