Give your small children a bath sometimes. Usually, mothers bathe the children, but bath time is an excellent opportunity for fathers to be with their kids. Let them splash around and play a little more than mom does. Teach your children to make wudu and pray with you. If at home, praying together as a family Jamat is better than praying alone.
Children love to call azan.
Make the youngest one the salat manager at home, taking care of prayer rugs, timing, and inviting everyone to salat. Take your children to the masjid with you. This is an excellent way for you to build a relationship with them as both a father and a Muslim. Be available for your children, and let them know that you are there for anything they want to discuss. If you are not available to talk to your children, somebody else probably will be, and it may be the wrong kind of person.