Q: how can I keep my kids open up to me?

The key is to understand why kids may not want you to be privy to the comings and goings of their life:
1). You are likely to give unwanted advice. Kids think they know it all and often when they come to you, it is more for a listening ear then for advice.
2). They do not share any common interest with you. They may feel that there is no point in sharing their interests with you if you are not updated on current trends.
3). They may be afraid that you would scold or criticise them.

To foster a closeness with your child even as they grow older, it is important to

1) lend a listening ear and try to hold back your advice unless they specifically ask for it

2) Keep abreast of their interest even if it means listening occasionally to the latest teen pop sensation and showing interest when they share their latest obsession. You were like them once. You can also find common activities to do together.

3) When they own up to mistakes, eg. If your child was absent minded and lost his water bottle or wallet, instead of being quick to label your child as being careless, ask how he tried to solve the problem and reinforce positive behavior instead of critising them. Eg. ask how he might try to be more careful in future. There would be times where you might need to step in and take action, showing your authority as a parent, however these should be kept to a minimal.

As a parent, it is always a balancing act on where to draw the line - being overprotective of your child and allow them to make mistakes.