Hi,
In my experience I have found that the adult that is with your child needs to watch the clock (very close) and have the child go to the bathroom every 45 min-1 hour and about 30 minutes after she has a drink. If she has a successful day (no accidents you could reward with a sticker, extra bedtime story, candy, or whatever you feel will work for your daughter. I have potty trained two children, one boy and one girl, and I am a preschool teacher who has worked with families going through the same trouble as you. THis is not an easy solution for the adults as it takes a lot of awareness and patience but it has worked every time for me. Often it seems that the child gets engaged with an activity and does not want to be seperated even for a minute to use the bathroom. Have the accidents been happening at a particular time, place, or day? It might be worth trying to identify a pattern to see if there is something that is bothering her, if she is "over" engaged, or if she is trying to get your attention.
Good luck and remember everyone learns this skill eventually!
C.