K.L.
With both my daughters we made them go potty right before bed and then we woke them up later in the night and put them on the potty. It may take a little while to figure out just the right time to do it--wait too long they've already peed, too early they won't go. It ended up being about 11:30 that worked. We had to do this for a couple of months, but then they started making it through the night on their own. My 3 1/2 year old still occasionally had an accident, but very few. Also, watch how much she is drinking before bed and don't let her have too much water.