I waited until my daughter was 18 months. Up until then she would only take 1-2 ounces and that's it. Finally a friend advised me on a different way and I did it. Basically went "cold turkey". By this time she was eating lots of solids, so one Saturday I said no more bottles, only sippy cups. Of course she through a fit, wouldn't drink more than a couple of ounces for most of the day. Then the next day she drank completely out of the sippy cup, full 8 oz, and never went back to bottles. But, like I said, my daughter was older and it worked like a charm, not sure if that will work on a smaller baby. I have a 15 month old son, and he won't even drink a sip out of a sippy cup. I know I could not do the cold turkey thing with him right now, but I am going to definitely try it again when he is a bit older.