Order and Technique for Painting a Room

Painting Plastered Walls

If the walls or ceiling you wish to paint have been recently plastered then they will need to be completely dried out before any paint should be applied. This could take several weeks depending on the depth of plaster. (Typical drying time for new plaster is 7 days for every 5mm thickness.)
It is sensible to wait because if paint is applied to a plastered surface that has not dried completely, any moisture will effectively be trapped and could result in mould growth and the paint may not key as it should, resulting in flaking and peeling.
New plaster should be sealed with a mist coat of emulsion diluted 15% - 20% with water before applying two neat top coats.

Paint the ceiling.

Use a brush to cut in round the edges and include any coving at this stage. Bring the ceiling colour down onto the walls by 25mm to cover over the caulked joints then use a roller to finish off. Leave to dry completely then repeat the process.

Paint the walls.

Again, using a brush cut in round the ceiling, windows, doors, light sockets and switches and use the roller to fill the bigger areas in. If using two different wall colours, overlap the lighter colour onto the darker wall 25mm and cut the dark colour into the light one. To cover you will need to apply two coats but if changing colour significantly three may be required.
Having finished the ceiling and walls its now time for the woodwork.

Paint woodwork

New timber should have any knots sealed with knotting solution to prevent the wood resin from staining the paintwork. Use a small cheap throw-away brush. Then first coat with a water based wood primer. When dry, second coat with a water based undercoat. If the woodwork has been previously painted, if in poor condition, after preparation, paint a coat of undercoat followed by your topcoat of choice. Always use an undercoat as it helps the topcoat to adhere. You can either bring the radiators in with the trim colour, or if you wish you could use an eggshell paint in the wall colour. If you were going to use wallpaper as a finish on the walls, the order would change to:
Ceiling, woodwork, wallpaper.

(The information given is for guidance only. You should always follow instructions on the label, and seek your own independent advice)