The keything is to lower your core body temperature. Once you have done that then all the other tricks like fans, open windows etc are so much more effective.
I have showering before bed as I feel it is a waste of time as I have to do it in the morning anyway, but having done some research, one of the fastest ways of lowering your body temp is a cool shower. Otherwise, although you may have a cool head or whatever it takes very little time to heat up again because it is warming your from the inside.
Your head does not hold any more heat than any other part of your body in reality - there are lots of bloodvessles on the head so it is a good idea to have cool wet hair as it helps maintain bosy temperatures, but anywhere where you have blood close to the skin will do that same. One really good top for during the day is to run your wrists under cold water as that has the same effect beings as a heck of a lot of blood goes through there so it helps to cool it down.
As I said though, all of this is only stop gaps if you don;t lower you core temperature to start with, so cool (not cold) baths or showers before bed!
