The problem with selling a nice bike that's relatively new is the belief it's worth what you think. Right now 2014 bikes are being discounted. Also when buying used, many buyers will spend additional money on things like different stems, bars, bar tape, saddle, tires, etc. All that is negotiable or at no cost with a new bike.
Most sellers start with too high a price. I just did. I listed a cyclocross bike late Thursday evening on CL for $700. I got a couple inquiries but that was it. By Sunday evening, my listing was 2,000 from the first page. I checked similar bikes and lowered by price to $400 the next weekend. It sold within a couple hours and I had 4 or 5 other serious inquires before I took it off.