Michael Brown recently did a radio program on the subject of time management. I highly recommend listening to it. He cites some statistics and makes many good points. I've discussed this issue in the past (for example, here and here). It's a subject that's especially important to address in a context like twenty-first-century America. I suspect that it's neglected, in part, for the same reason some other sins aren't discussed much. People don't want to step on too many toes.
Think about your priorities. Think about the details of your life: how you spend your travel time to and from work, what you think about while you're at work, whether it makes sense to do the housework and yard work you do, whether your relationships make sense, etc. Review your life often. Memorize and think about passages of scripture concerning themes like the primacy and greatness of God (Jeremiah 2:13, Ephesians 3:8), how brief and fading this life is (2 Corinthians 4:16-18, James 4:14), and how you're influencing other people (Psalm 102:18, 2 Timothy 2:10). Study church history. Think about how other people have lived. Consider what others will think of how you've lived.