I wouldn't advise watching TV or doing puzzles in bed, both will stimulate the brain too much. She would be better reading a (non-exciting) book to help her drop off.
The bedroom temperature should be slightly chilly but not cold, and the bed itself should be a comfortable warm temperature.
I also agree that she should do some exercise, preferably outside for the fresh air, and should avoid any afternoon naps or anything which may disturb later sleep.
Here are some other tips:
http://www.mercola.com/article/sleep.htm