Becoming more involved in your child's life can take a lot of different forms. At every stage your children can benefit from your involvement. Read with young children. Join the elementary school parent teacher organization. Chaperone a school event. Volunteer as a coach, or ask your child's coach in what way she/he could use your help. Take a rainy Saturday and turn it into a family movie night.
Take time to be a positive and supporting part of your child's life. The resources and links here are a great starting place to learn more.