A.C.
I remember trying to get my daughter to switch to the cup between 10-11 months, and it was pretty tough at first. She would get really upset and cry and all that, and I'd end up giving her the bottle again because that's what she wanted. Plus, I was always so worried about her not getting enough formula if she didn't drink from the cup. What I ended up doing was getting the platex cups with handles (they have soft tips), and then I first replaced her bottle in the morning with a cup because that's when she was the hungriest and most likely to drink it, and it usually worked; if it didn't I just didn't worry about it, but I didn't give her the bottle (I ended up packing the bottles away so I wouldn't even be tempted). After a day or two, she realized I wasn't going to give in and give her the bottle, so she drank out of the cup, then after that was working for a few days, I replaced her midday bottle with a cup, then eventually her midmorning one and afternoon one, and finally the bedtime one, as that is generally the hardest one to give up. This is what worked for us; it was definitely tough at first; you've gotta be willing to put up with a little crying and frustration, but it does work. Hope that helps!