Well, apart from obvious things like
"make sure you don't dream about the Cybermen, you know how that makes you have nightmares"
But maybe I should also add:
"Daddy needs to be up early tomorrow so I'll make you a deal; you have to make sure I'm up. If I'm not up by 8:30, I'll give you a pound for each ten minutes I'm still in bed".
Of course, I'd also recommend that if you're going to say something as stupid as this it would also be a good idea to not stay up till 4am messing around with i-tunes, music backups and the coding on the weblog.
In the end it cost me £9.
And today we somehow miraculously ended up in the toyshop with £9 burning a hole in Molly's pocket.
Tonight she casually asked me if I wanted to be up early again tomorrow morning and maybe we should do the ten minute penalty thing again.