It seems like family prayer used to be more of a tradition that it is now. But you can help correct that situation. The "Pray!" part of the NavPress site offers some good tips. To get you started, there's Family Prayer 101. But don't stop there.
Digest and adopt at least some of the ways to make prayer a natural part of your day. Then top off your reading with " Prayerworks for our family" - a personal tip from someone who tried it for their extended family.