We say grace before meals - have done since before the kids were born, so they have never known any different.
Prayers before bed time are a bit sporadic - sometimes we get into the habit of saying them, but I'm not very good at routines. And that applies to me, too. Despite the fact that I am, in fact, employed by the church
We make Sunday a special day - church, family stuff, a nice meal in the evening, with a proper pudding like Grandma used to make and a candle on the table.
I suppose I count as CofE. we don't say grace before meals I say prayers myself before bedtime but with DS1 We have a chat about reasons to be thankful and general best bits of the day when he is in bed.
In terms of how to introduce prayers with children, DD1 loves "teaspoon" prayers.
T is for thanks S is for sorry P is for please
So we can think of things to say thank you for (the easiest place for children to start), we can say sorry for things we've done wrong (harder to grasp until they are about 5 yo) and we can ask for things we'd like to happen. But we also have to acknowledge the fact that God is not a magician, shopping list or fairy godmother and prayer is not just a magic way of getting exactly what we want!
I have a few minutes chat with ds(4)before he goes to sleep, after his story. Sometimes we just talk about the day, sometimes we say thank you, to each other and to God, for good things and sometimes we ask for help with things we are worried about. I sometimes say sorry to ds if I have been grumpy and he will say sorry if he thinks he has done something wrong. Then we might ask God to help us start again in the morning, without the grumpiness. Sometimes we go for ages without really praying, just chatting every night. We don't say grace, but if we have a special meal we will say thank you at night.