Flowerless Orchid

The last flower fell off my orchid today whilst I was at school.now I know I am meant to cut it down once this happens but I don't no how much or what to do for the best.I want it to come alive again when its ready and I've never been able to do this.I usually kill them so any advice would be greatly appreciated.

On a more usual and boring point it was a busy day at school....again.hopefully it'll get more interesting as the weeks go on.