How do I paint a room?

[Thisrabbitthatrabbit]

I know it seems a stupid question but we rent our house and I don't want to mess it up. (We have permission)

The wall is a cream colour and has some marks on it, mostly from DS and his mucky finger prints. I just want to paint the same colour over the top to freshen it up.

My plan is dust sheets on the floor, painters tape around the baseboards, switches etc. A 5L of dulux? Is this a reasonable quality? We are going to use sugar soap on the grease marks before paints and just wipe the rest down with soapy water. A roller for the most part and go round the details with a smaller paintbrush.

Am I missing anything? Should I use a primer? Will old sheets protect the floor well enough (carpet)?

Half of the room seems to be wallpaper that has previously been painted, can I just paint over it?

How do you paint behind a radiator?

If the marks are greasy, use a stain stop paint (put it on with a small gloss paint roller for a smooth, even finish) before you paint the walls or your efforts will be wasted and the grease will start to show through.

You don't need primer as there is already paint on the walls.

Get a radiator roller for painting behind the radiator. It's a small roller on a long handle. Line the roller trays with either the plastic liners you can buy or cling film to make cleaning up easier.

I thought the sugar soap would prevent it showing through. But I didn't know stain stop paint existed so that sounds like the way to go.

Cling film in trays is a genius idea! Thank you.

Wikipedia will have directions.