• Take a decent picture. You'd be surprised to see how many people will post an expensive item and then have the worst blurry cell phone photo you've ever seen. Daylight is best so if you can put the item outside (in the shade, not the direct sun) or have a nice light part of your apartment take the pictures there. Take a shot of the whole item and a detail shot of anything relevant.
• Name it correctly. When titling your listing, you want to be specific and clear. Please avoid using the term 'modern' if it isn't. If it's mid century write that. Please don't write 'great sofa!!!!!!!!!!!!' that doesn't tell the buyer anything and any amount of superfluous exclamation points will only make your listing seem more dubious.
• Keep the description short. No one cares to read the biography of your piece (maybe unless you're explaining the authenticity but even then, keep it simple, we're not on craigslist to read novels). 5 sentences max that explain the dimensions, the condition the item is in, the color maybe and how old it is. We make most decisions based on the picture, so don't spend too long on this.
• Use a nice large picture. When you put together the posting, craigslist offers to upload your photos for you. Don't be fooled, they will look crap and small. Instead use a free site like tinypic to upload your shots and have them resized to 640x480 pixels. They'll generate code for you to copy and paste into the body of your listing. This will look awesome.
• Add keywords. When people do searches craigslist scans the body of all the items posted. So if you're selling an eames fiberglass chair, you probably called it that in the title. But in the body you can add a list of key words like: 60's, mid century, shell chair, charles and ray eames, modernica (cause they make the reproductions), vintage, etc. Also if you're selling a bunch of stuff you can use the same keyword in each one. For example I could have LJ2009 be the keyword and let people know in the body of the posting. Then if they search that keyword, all of my listings will come up.
• Price it correctly: Craigslist is notorious for having inflated price points and most people are willing to negotiate a little. That being said, if you have an old pottery barn chair that was in 5 years ago and that your dog has been living on in the meantime, price it accordingly. If your mid century credenza is listed for $900 and there are other similar ones for $400 then you're not going to sell yours quickly.
What other tips are there for craigslist postings?