I don't know about girls, but here's a tip for guys.
When waking up in the middle of the night to take a leak, rinse your face with some water to wake yourself a bit before relieving yourself , you won't want to be peeing in a half awake state.
Happened to me a few times, was peeing in a half awake state and when I'm done, I found out that either I aimed at the wrong direction or I'm still a few steps away from the toilet bowl.