It might be just my boys, but I think it's a rare boy who understands how to manage his time well. Too many distractions, too much to do. How does one stop and learn the fine art of time management?
As with so many things, our children learn from our example. When I say aloud, "Hey guys! We need to be at the orthodontist's office at 10, so we'll have to be in the car and pulling out of the driveway by 9:30", I am teaching them time management without even trying.
The lack of skilled time management tends to show sometime during high school, when boys are juggling academics, perhaps a sports team, a musical instrument, a part-time job, and a social life. These years are a great time to pass along some hands-on help and teach them what you know about having your hands in lots of pies, as it were.
I recently took my three oldest sons (20, 18, and 15) on a date with the intent to help them map their next few months. Using Amy Lynn Andrews' very helpful e-book (affiliate link) Tell Your Time, we wrote down their goals and responsibilities, the things they had to do and the things they want to do. I think they were somewhat surprised by the lists they'd created, and in the end, I hope they had a better grasp on how to rearrange their lives to make better use of the 24 hours they have in a day.
There is a time for everything, and a season for every activity under heaven. Ecclesiastes 3:1