Well, this forum is for selling cars - clearly! So how can you get people to buy your car? Keeping in mind this is a Mercedes forum, you should be selling a Mercedes. But...

1) Where is the car?
Too many people forget to say this! If you can't tell me where it's located, I can't be bothered to ask because you must not really want to sell it Even if your location is listed on your user name, it doesn't matter. Say where the car is - hell, give an address if possible, so local members can drive there and view it! Trust me, this WILL get you more replies
2) Asking price
If you're selling, you need to let us know if you're dreaming or if you're realistic. A price - even if it's what you are willing to bargain down from - will definitely help a potential buyer decide if they want to make you an offer, or if they should look elsewhere.
3) Pictures
This cannot be stressed enough. Keep in mind that you're selling a car over the internet. A buyer has to assume (and rightfully so) that you are pointing out the best parts of the car, and not the worst. So you need to include pictures - even if there's rust, or a bad paintjob. It'll tell us a LOT more accurately how bad the cancer is, what the car's realistic value is, etc. If you post ANY thread about selling a car here, and don't include pictures, then you might as well not post at all. Go to Imgur. Sign up. Create a public album. Link it. http://imgur.com/
4) A thorough description
Let's say you're selling a 6.3. Everyone on here knows what that is. You don't need to tell us how rare it is, how much horsepower it has, etc. Let's say you're selling a 300D. Don't try to tell us it gets 40MPG - we all know it doesn't. So what should you tell us? Well, start with the basics: Mileage, how often you changed the oil, how long you owned it, etc. Most importantly: Why are you selling? A buyer assumes 2 things: You're either getting a newer car, or there is something wrong with the old one you aren't disclosing. So if it IS because something is wrong, be honest - don't waste your time and ours, we will find out, then we'll tell other buyers right in your thread.

I would like to see others comment in, but I do believe this is a "Public Service Announcement" that will only benefit both buyers and sellers on the ShopForum