I hope you get some good ideas, because my 2 year old sucks his thumb and I don't know if there are any ideas that work. I sucked my thumb as a child, and no matter what my parents did, nothing got me to stop. I had a bump (callous..?) on my thumb from all the years of sucking it, and my son is starting to develop the same thing. The embarressment of having that there is the only reason I finally quit, but I was pretty old. At times even when I was 11 or 12 I would wake up to find my thumb in my mouth...force of habit I guess!! So maybe I can get some ideas too, but I am not counting on it...I think they just might need to grow out of it. My husband put a small glob of lotion on our son's thumb one day, and it stopped him for a while, but eventually he didn't care and went back to sucking. Oh yeah, one more thing- I never needed braces because of the thumb sucking. I had a slight overbite, but now as an adult, people think all the time that I had braces as a kid because my teeth look good. So you may not need to worry about that factor as she grows.