I've had very good results selling my last SEVEN used bikes on Craig's List and/or the Forum websites of the brand and model I was offering for sale.
Some sell very rapidly, others take a little more time, depnding on the time of year. Winter seems to be the worst time to sell a used bike, or new, (ask a dealer)! Posting lots of photos and information is VERY helpful!
Good luck with your sale!
1CW