You're sitting in class and the teacher gives out an assignment. Maybe you groan (at least inside) and ask yourself why you have to do this pointless paper. I'm going to tell you now, though, it isn't pointless. You may say, "But you don't even know the subject!" That's right, I don't, but there is more than just a grade at stake for those of us who follow Christ, no matter what task we are given.
There are many ways you can "work at it with all your heart, as working for the Lord, not for human masters," as Colossians 3:23 says. For one thing, your attitude about work is called to change just by your reading that one verse! When you're working for God, you can't complain and fuss or pout. If you're the only one not complaining, you'll be noticed, and that gives you the opportunity to give God the glory! Is it worth joining in and complaining about a task when you can, instead, shine for Jesus by putting your pride aside?
Philippians 2:14-16 "Do everything without grumbling or arguing, so that you may become blameless and pure, 'children of God without fault in a warped and crooked generation.' Then you will shine among them like stars in the sky as you hold firmly to the word of life."
Also, your work ethic is important. A work ethic is the standard to which you do your work, and the manner in which you accomplish it - if you have a good work ethic, your motivation to do your best drives you to complete tasks on time, to produce quality results, and to put true effort into what you take on. You're not trying to be a teacher's pet by doing your best - you're trying to please your Creator, who's given you the abilities to succeed.
Another way you can shine is to make sure you are honest in all manners. This is especially hard for some students. It's easy to copy someone else's math problems when you "didn't have time" to do all of your homework because you were studying for another class's tests; easy, and wrong. It's easy to read something online or in a book, and seeing it is worded just so perfectly, copy that into your paper, and "just not say" it's someone else's words; easy and wrong. It's hard to do the right thing, but it's worth it.
From your thoughts to your actions to your words, you will have many opportunities every day to shine for the Lord. Will you choose to do the right thing, or will you choose the easy way out?