Keeping cool at night helps promote the sleep hormone melatonin, which is key to a good night's sleep.
If you aren't sleeping well at night check out the how warm it is in your bedroom. Some people, smother themselves in blankets, wear thick heavy nightwear and have their heating turned up rather high.
When your body temperature is too high, you feel more alert but when this temperature drops your energy and ability to concentrate falls.
At around 11pm core body temperature drops slightly making you feel sleepy and ready for bed. At around 5am, your body temperature is at its lowest and you are likely to feel very tired if you have to get up at this time. However, by 7am our body temperature gradually rises to trigger us to wake.
Get ventilation if you can - a door or window slightly ajar
Keep heating on low or off completely.
Set your heating to come on at the time you want to wake up.
Keep your room cool in the summer by closing blinds earlier.
Use cotton sheets
Ensure duvet is low tog rating or replace with blanket
Wear cotton night wear; better still go naked!
Take a hot bath or shower 90 minutes before bed time, the cooling down afterwards will help you to feel sleepy.
Try adding lavender oil to bath/shower or as a skin tonic after drying (be careful with quantities as over use can stimulate).
Place a "cold" water bottle or ice pack in your bed to cool down the sheets 30 minutes or so before bed time
Avoid caffeine and sugary drinks