I agree with jazmic, CIO never worked for my oldest he was 3 before he slept by himself. Nothing seemed to work with him. However my other 2 and all my dck's CIO and have done pretty much since they started or I the case of my own did from about 6 months. Aim for a dark room, full tummy, play pen to ensure they are contained, however some children hate being in play pens IMO , and a few safe toys to play with if really needed. I also find if you don't constantly listen, your heart doesn't break quite as quickly. And do not go back in to check (unless you are worried) as this enforces the idea of if I cry they will come! Most of all hugs and good luck!!! Let us know if you find the answer!!!