'My First Little Fears' - tips and tactics

Just thought I would post, say hi, and let people know how I got on when I ran my first game of Little Fears. Someone might find it useful.

First off, my group are normally die-hard D&Ders - but there was a session 'empty' between campaigns so I was volunteered to run 'something'. I chose Little Fears. Unfortunately, when the players heard that it was a game about playing as children, they went a bit daft. They made characters easily enough, but I couldn't get across to them the fact that it wasn't all going to be sweetness and light.
And I suppose the fact that I have a, well, unwise style to prepareing for games didn't really help. Y'see, I don't.
So there I was, with five players all wanting their characters to steal milk from the neighbours doorsteps, or make prank calls to Childline. I decided I was going to come down hard on the worst offender. I set up a bit of a plot (flying by the seat, every inch of the way) and had one of the characters sent home. I ran the DMed the rest of the players for a couple of moments, then took the 'offending' character outside. He then had a very uncomfortable encounter with a possessed Social Worker.

This served quite a few purposes - scared the character almost witless, got the player in a MUCH more appropriate frame of mind, made the rest of the players nervous about being 'taken outside' and the offending character became the fear seed for the rest of the group - jumping at everything and setting everyone else off.

I was rather pleased with myself.

Anyway, I'm trying to write up the whole thing as a one off adventure so that others can play it. But does anyone else have useful little tricks/tactics for 'dealing' with players, or for getting just the right atmosphere?