Materials:
Water
Cotton bedding
Oscillating fan
Ice pack

1. Invest in crisp, cotton sheets as your only bedding.
2. Keep your bedding in the freezer until fifteen minutes before bedtime.
3. Take a cool shower.
4. Go to bed with your hair wet.
5. Sleep naked.
6. Make the air move with an oscillating fan. 
7. Keep ice water on your nightstand.
8. Place an ice pack under your feet.
9. Place a wet cloth on your forehead.

via howtodothings

1. Plug in your fan and turn it towards you.
2. Try the towel method. 
3.  
   Take a cool shower, bath
4. Consider using the "Egyptian Method"
5. Take a pair of cotton socks
6. Sleep in a 'spread eagle' position,
7. Try buckwheat pillows or futons. 
8. Get a few blocks of "blue ice," 
9. On really, really hot nights or days
10. Get out of bed and splash cold water on your face 
11. Dampen a hand towel
12. Wet Your Face
13. Get Naked 
14. Sleep Downstairs
15. Chill Your Pillowcase
16. Run Your Wrists Under the Cold Tap,

via wikihow