Choose a healthy runner which has produced one or more leaves, and remove any stems emerging from the new leaves, while keeping it still attached to the parent plant. Fill pots with multi-purpose compost. Place the strawberry runner on the surface and hold it in place using a u-shaped staple or a piece of wire.
Keep the compost moist at all times. Don't snip off the stem linking the new plant to its parent – keep this until the new plant has developed strong roots.
As soon as the plants are strongly rooted, snip off the stem connecting it to the parent plant, and plant in into a larger pot, or out into prepared ground.