If you have gone back to school, or are just taking a class for your personal enrichment, work when your teen studies whenever possible. While you are there, point out other adults who have gone back to school. This is another way to show your teen that education and good homework habits are valuable forever. When your teen was younger, you made a point of telling her you loved her every day. Now that you're both busier, you may have gotten out of the habit.
Little things mean a lot.
Try to do one or more of them each week. Tuck her favorite candy in her backpack where she'll fin it at school. Pick up a copy and wrap it with a ribbon. Your presence says more than your presents. Whatever her interest, make time to be there.