Run a humidifier in the room to add moisture to the air. Dry air conducts static more readily. If you don't have a humidifier, boil a pot of water on the stove.
Rub one or more dryer sheets gently over the surface of your couch to neutralize static.
Spray the couch with an anti-static spray, which you can find in the laundry section of most grocery stores. Spray from at least a foot away so that you don't saturate the couch with the spray.
Place a cotton slipcover over the couch. Cotton is less likely to conduct static charges.
Wear cotton clothing so that you reduce the chance of conducting static when you sit or lie on the couch.