This year, consider making a New Year's resolution that you will talk to your tweens and teens about important things on a weekly basis. Let them know how much you love them some weeks, and what you worry about on others. Ask them about their friendships or talk to them about high risk behavior regularly. Let them know why you want them to avoid the things that you know will hurt them. Address things that concern you about what you see happening with them or to them. Even when they think they know what you are going to say, they know that they need to hear it from you more than once.
These conversations are not lectures, although sometimes they will be one-way. Remember that you've had time to plan this conversation, they haven't. When you mention something, expect that it will be brought back up later. Remember that these conversations go the best when they are side-by-side, not face-to-face.
Resolve that you want your kids to know what you think. They need your wisdom, even if they don't think they want it. They are developmentally designed to roll their eyes at what you say (figuratively or literally.) Make a joke about it, or ask them to wait until they turn around to do it, but let them know that you think their lives are important, what they think is important, and making good decisions is important. You love them enough to expect it from them.
Most of all, though, resolve that when they talk, you will listen.
For some quick tips check out 7 Tips on this website. For an in depth discussion with some great ideas, check out Staying Connected to Your Teen by Michael Riera.
Happy New Year!