I've got 3 daughters - 6, 3 and 1.
Along with sound machines, sleep sacks have been life savers for us. We went through a variety of them - each of our kids slept better in different suits. But they were complete game changers for us.
I'll be honest, our oldest was a rough sleeper, but our second 2 have been super easy when it comes to sleeping. Heck, our 1 year old (actually 18 months) has been sleeping through the night since she was 3 months. We don't even have a bed time routine for her really - change her diaper, put pajamas on, put sleep sack on and hand her a bottle (she feeds herself). At 10, I sneak in with another bottle and put it in the corner of her crib. At some point in the middle of the night, she wakes up and feeds herself again.