"If you've never tried it, don't touch the room. Get another sheet of
plasterboard, some new multifinish or plasterboard plaster (as someone

It's fresh.

has to all come off again) and have a crack on the spare plasterboard.

Good idea...

A guy who used to do skimming for us told me once a common error is to
make the mix too dry, and it becomes more difficult to work. Prepare

Ahh right - I was thinking drier would make it stick easier on the ceiling.

the surface either by washing (to make wet) or PVAing (to seal) and

Gonna use PVA

Assuming you get it all on, make reasonably smooth with the trowel and
leave for a while. 10-20 minutes. It should now be firm but not set
and you can use a wet trowel to ontinue smoothing the surface as far
as necessary. Do it long enough and the final result (after drying)
feels absolutely smooth with no grittiness.

Ahh this is the bit I wasn't sure about - how long to wait before trying to
smooth off.

the walls, one at a time. Make sure all the nails in the plasterboard
are galvanised or otherwise rustproof, otherwise the heads will rust

They are plasterboard screws which I think are okay.

Cheers, Rob.