1) The bike must be perfect. That means nothing frayed, everything clean, every adjustment spot on, aligned and reset to optimum proportion (stem versus saddle drop, seatpost height, saddle level), bar tape clean if not new. All bearings right. Tires clean, if not new. Rims true and clean. Chain spotless, if not new. Again, make certain that everything is working exactly right.
2) Excellent photos. Choose a plain neutral background. Shoot from the drive side. Clear shots drivetrain, brake calipers, lugs, hubs, rims, head badge, saddle. A few shots from non-drive side, too.
3) Craigslist will require the serial number in the listing.
4) Demand that the responses include a phone number and a name. No name or phone number, do not respond. If the response has a name and phone number, you can begin a dialog over Craigslist contact e-mails. Share your phone and address only with those who contact you earnestly.
5) Never negotiate price over the phone or via e-mail. I rarely if ever discount from my asking price. Currently, bikes are selling above previous market values, so price accordingly. It's a seller's market.
6) Meet where it's safe to test ride. Bring your own bike, too. Ride alongside the potential buyer and explain anything about which they have questions.