Take down any photos, mirrors and ornaments and store them somewhere safe.
Move furniture. If you have the storage space, you should completely clear the room of furniture. If that’s not possible, just move it to the centre of the room. Your painter should bring protective sheets to the job but it’s a good idea to check before they arrive.
It’s worth removing curtains and blinds to protect them from paint splatters. This may even be a good opportunity for you to run them through laundry.
If you’re readying the walls yourself, make sure you finish the day before so the painter can start straight away.
Vaccum the carpet so there’s no dust between the carpet and the skirting. The last thing you want is a gust of air blowing it onto the new paint before it dries.
It may sound obvious but make sure you have enough paint. There’s nothing more disruptive than having to run to the paint store halfway through decorating.