First Things First is an excellent book/audio tape by Stephen Covey. I really recommend you to buy, read and act on the information in this book. It is aimed at people at work, but you can equally well apply this whatever situation you find yourself in.
Covey suggests that activities can be divided into 4 categories:
Activities that we have to do and so we make time for them. It can feel like we are being very productive. It can be very exciting and make us feel important.
Activities that are important to your core values and your vision but do not have any urgency attached to them. Activities such as spending time with your family, taking exercise, relaxing, long-term planning, anticipating and preventing problems, self-development activities, etc. fall into this category. We intend to do these things, but often get involved in activities in the other quadrants instead.
Activities that other people might feel
These are activities that use up a lot of time, but do not achieve anything. Note that genuine leisure activities are not included in this category, because they are important. People often go to this quadrant to escape from Quadrant I and III: Recreation in the true sense of re-creation is a valuable Quadrant II activity. Quadrant IV is not survival; its deterioration.
Read Covey's book to learn more about these 4 categories and how to manage time practically in your own life.