Our pedi said our girls are ready to start learning to drink from a cup. And did you use water or EBM/formula? What type of cup did you first introduce? Regular, sippy, something different?
Our first cup was The First Years Take N Toss. They come in 5 ounce sizes. Perfect for little hands. They also do not have a valve so that when they are able to tip it to their mouths water will fall out of it so they actually get something and dont have to work to hard to get it. Then we moved on to cups with valves and straw cups.
I also second the Take N Toss. I have some many sippies in the graveyard & found the more basic, cheapest ones to work! All I can tell you is to experiment until you find the perfect one!
I third the Take N Toss. We tried these fancy Advent ones but they had to work too hard to get anything out. At least the Take N Toss kinda leak a bit so they know that something comes out of the cup. I have only put water in it and still give them their formula in bottles.
We have tried tons, and I now have my dd drinking out of a Nuby without handles. I can occassionally get my son to drink out of a nuby that has handles.
We started with Nuby, but they have learned to bite the spout and rip the valve, so they drip everywhere. Now, we are using the Gerber Graduates ones. I like them better than the Playtex ones, because the spout is a little softer. The take n' toss are great, but my girls like to make a mess with them.
WE had great success with the NUBY straw cups with handles. Although we didnt introduce them until 8 months, and by 9-10 months they were completely on the cup (even my bottle baby, as I nursed one and pumped for the other after she weaned at 8 months). My pedi always said if you're going to give them liquied give them something with calories but I have skinny babies too. If you can give them ebm/formula in their cups at a cool temp that would be beneficial for you later when you make the transition to cold cows milk/goat milk or whatever kind of milk you'll offer.
My two are just starting to get the sippy cup thing. We are using the Born Free trainers. They don't leak at all, and even I couldn't get anything out by sucking on it! However, if you bite down and suck, the liquid comes out. Both boys can hold them on their own and get about 10-15 ml out before dropping it. The other nice thing is that I think it makes their gums feel better because they're teething.