Drink plenty of water before the nap, don't lie in the sun/ in a stuffy room, and don't nap for more than 30-40 mins!

To take the most effective nap - when you wake up feeling refreshed rather than groggy - always nap lying flat on your back in a soldier position. Stop yourself from getting under the covers or rolling into a foetal position - you want to stay in a shallow sleep and not go too deep. Use lots of pillows so your face doesn't get puffy either. And only nap for half an hour or less.

I just lay on the sofa and start counting backwards from 100, I am very quickly asleep and just have 15 minutes which I class as power sleep.