How would is she? If she's really young like 3-5 she might be having nightmares. If shes like 6-10 maybe somethings wrong in school. And if she's a preteen or teen (12-15) maybe it's a crush or boy probs. I'm 13 and to make me fall asleep I either think abt wat I want to dream abt that night and start the story abt it and then sooner or later I fall asleep or I turn on my iPod and put one headphone in one hear and turn it on low and it makes me fall asleep. Good luck :)
I have always had trouble sleeping, and I can tell you that the best way for me to ensure a full night's rest is to work very hard all day. After going to school and then work, my mind and body are usually exhausted enough that I can get a decent night's rest. I don't sleep well at all during weekends, vacations, or any other time during which I am not constantly assaulted by academic and occupational demands.
Is she having trouble going to sleep? Have her do a bit if relaxation breathing and quiet or darken her invironment where she sleeps. If she can't stay asleep, lower the sugar intake and take a small amount of nyquil. If she is just waking up cranky, have her eat a banana in the morning. Potassium can really help change a persons entire attitude dyring the day. I promise, bananas can help change someones mood almost immediatly! Hope this helps!
Try talking to her.. Make her feel like she can be open to you.. Give her positive feedbacks. It might be an emotional problem. So give her the feeling that she can really trust you, an tell you whatever is going on in her mind.. Hope it helps!:)