We have been extremely successful both buying and selling on Craigslist.org. We have not had great success on other sites, even though they were paid adverts.
As others have said, detail it so it looks the best it can. Post a lot pictures and give a detailed description. I have found that brief ads do not bring results. If you show you are interested in presenting it, interested people are motivated to read the details and will pass the one-liners. Buyers have confirmed this multiple times. They have even quoted some of our information.
You will find scammers on craigslist, so be careful in responding via email. If we recognize it as a scammer, we flag that email. Our ads state, "We may only respond to emails very specific to this ad". And we hold to it. Our phone number is listed in the "Reply" tab. We require a phone call to give our address and no address until they say they are coming. A phone number is much easier to trace than an email. Also, we will not deliver without the buyers seeing it.
Be patient. Often, it doesn't take long, but at times it may. Consider this, a dealer may sit on something for months before making the sale. A person may not be checking craigslist daily or may sit on the ad for a few days. A trick we have learned is to delete the ad weekly, on Friday, and immediately repost the same ad. Very easy on CL. When the ad is deleted, it immediately gives you the option to repost-don't need to redo anything unless you want to make changes. This keeps your ad up front with no history of how long it has been listed. We have reposted ads and within minutes got a bite.
We never post an ad with the price OBO. That is an immediate flag that you will take less. You may get a low baller testing you, so don't be afraid to hold your price or come down a little-let them counter-they will if they want it.Tell them that you appreciate the offer, but want to hold the price, or hold for a better offer. We have found that the next person has paid the price or the person with the low offer decides it worth it. Be cautious with accepting anything but cash.