A clean velvet couch makes a bigger difference than you'd think. Here's the most effective method, plus the mistakes most people make.
Look at the tag for the cleaning code (W, S, WS, X). Velvet care depends on the fabric backing.
Vacuum the velvet with the upholstery attachment using gentle suction. Don't press hard or you may crush the pile.
Use a soft brush to gently brush the velvet in one direction to lift the pile and remove embedded dust.
Mix a few drops of dish soap with distilled water. Dab the stain with a damp cloth -- never rub. Test in a hidden spot first.
Let air dry completely, then brush again to restore the velvet pile direction.