Here I was with an old camera that I kept for way too long had depreciated so much I wasn't sure anyone would want it. I have sold many things on ebay or gumtree but my camera gear remained sacred to me. When the time came to sell my old D50 I wasn't sure anyone would take it. I learned a few things in the process. I just want to say that I don't encourange fast turnover of gear to begin with but there comes a time when limitations are reached. Here are some pointers.
1) Don't let your gear get too old
If you think that you are going to upgrade to the newest thing every 2-3 years don't wait until you reach year 5 to sell your unused equipment. Value of electronics in general decreases very fast. Camera technology is also improving every year. If you can use the lenses from your previous camera on your new camera great. That is a lot of savings. If not buddle and hurry!
2) Bundle your gear
Selling my D50 on its own is a hassle. It is hardly worth the cost of listing and shipping, let alone my time to do all that. However, bundle it as a kit with a couple of decent lenses and you can sell it for a little more and get some money out of it.
3) Keep the extras
Whenever we receive a new electronic we tend to discard the packaging, manuals and anything else that we won't use and takes up space. Don't. The camera is worth much more with all these extras. In addition, don't forget the strap, the lens hood and the charger. Nobody wants a car without wheels.
4) Sell it for what it is worth.
This is a tricky one but there are a number of ways to determine the value of your gear. First look at the used market. Take a stroll down Ebay and Gumtree and look what others are selling it for. Pay particular attention to auctions. Auctions that sell tell you the real price. Auctions that don't, tell you how overvalued the item is by the owner (or that no one really wants it and there is no need to list it). Sometimes people make the mistake and think that because their item is in better cosmetic condition than other listings it will sell for a higher value. This is a mistaken when it comes to old camera gear as age is much more of a factor. A camera with scuff marks will sell at the same value as a camera without. Anything from good to mint condition will more or less get you the same amount of money. Anything below good sells for less or not at all. Definitely don't try to sell your used gear close to the value of new even when it shows no wear or tear. Someone can always go to the store and get it mint, why trust you?
5) Present it in the best possible way
Selling an item is a long process. If you want the best price you'll have to put in the time. First take some good photos. Take as many as you can from all angles and show the scratches and marks. If you are honest people are more likely to trust your listing. If you own a lightbox use it. If your gear is dusty clean it. These simple steps can increase the value of your gear to the buyer. Finally put a good description. It isn't very important to put all the tech specs as people already researched these. Put the major ones and a little personal description what the lens or camera is good for. Mentioning the reason for selling is a good point as people want to know you are not getting rid of damaged goods (unless you are selling for parts in which case I assume you will put that in the description and the title of your sale). Overall be honest.
Some final thoughts
It might look hard to part with an item that you cherished and took care of but in the end there are a few questions you should consider. What is the minimum value I am willing to accept? If the item doesn't sell am I happy with it sitting in my cupboard collecting dust? Am I actually loosing money by selling it at the lowest price possible? This last question makes a difference. When people sell an item below average value they feel cheated. The reason being the comparison component (I saw someone selling it for x price). However, there is a value that people forget. It is the value of use. If your camera has been in a cupboard all this time doing nothing and the technology is outdated does it really deserve the price that you are asking? You got all you could out of it and I presume you are selling it because you have no need for it. Recovering any part of the original cost is still a bonus even if it is very little compared to others. Otherwise it would earn you nothing and just sit there being depreciated further.
Finally take a look at your market. Economic status, use of internet, availability are just some of the reasons you might find it easier to sell overseas rather than in your area or even country. Ebay is not always the answer if the local camera store is willing to take it. I hope some of this advice helps. Happy selling!