To begin, sand down the floorboards to key the surface, which will help the paint adhere. Take care to thoroughly wipe clean after sanding to remove any dirt or debris that will affect the paint finish. Then allow to dry completely.
When ready to paint, use a brush or roller and paint a thin coat of quick-drying floor paint. Start at the far end of the room and work your way back towards the door - to avoid painting yourself into a corner.
Leave to dry before applying the next coat - a good time margin is painting one coat in the morning and overcoating late afternoon, or leave overnight if you have time. Just make sure you leave 6 hours between coats. If any dirt has settled, wipe it away with a cloth so it doesn't spoil the next coat.
It's important to leave the floor until it's totally dry before you move furniture back into the room, and when you do move furniture back in ensure you lift it in rather than drag across the floor. For example, International's Quick Drying Floor Paint is tough and hard wearing but if it's not left to harden up for a few weeks before furniture is dragged across it the surface may be damaged.
Project and image courtesy of International Paints www.international-paints.co.uk