I have all of my children sleeping in the same room except my noisy screecher upon waking is in the next room. Not that it slows her down much for waking the rest of the children, but oh well, she sleeps a solid 2 hours before she wakes.

When I have new children start I sit beside them for as long as it takes for them to learn that they are going to lay down and sleep. I keep laying them down again and again and shushing them and patting their back and I keep hoping that it won't take weeks.