First and foremost make sure you drink plenty of water during the day to keep your body hydrated and cool while you are sleeping.
Make sure you can count on cooling mattresses or toppers for sweat-free nights.
Dehydration is a common cause of not being able to get to sleep, and it is known as insomnia.
Keep a glass/insulated container of cold water by your bed in case you wake up hot and uncomfortable.
Carefully chose the coolest part of the house to sleep in, if it is not your bedroom, temporarily move there.