Wipe the spill immediately with a damp cloth if it occurred on a hard surface. Blot the stain with white paper towels to remove the excess if it occurred on an absorbent surface such as a sofa or a carpet.
Mix a few squirts of dishwashing liquid with warm or hot water in a bowl and sponge the stain. Rinse the sponge every few minutes and keep sponging until the stain has gone.
Pour white vinegar, vodka or white wine over the stain if it has dried. These appear to act as solvents on red wine. Leave the stain for 10 minutes before sponging as before.
Mix one part dishwashing liquid with two parts hydrogen peroxide in a ceramic bowl if nothing else appears to shift the stain.
Test the mixture on an inconspicuous spot of the furniture item. It can have a bleaching effect, which might be more unsightly than the stain.
Pour the mixture over the stain and leave for five minutes.
Blot the mixture up with white paper towels and sponge the stain as before.