Regardless of how much effort you put into your item descriptions (and you should always try and be as thorough as possible) potential buyers may still have questions to ask before they place a bid.  This guide will hopefully help you answer these questions in way which is mutually beneficial for all parties involved.

Firstly, as a seller you have to realize that these questions are from potential buyers.  They're interested in your item, and this shouldn't be overlooked.  This is an opportunity for you to shine.  You should do your best to respond to all questions promptly.  This instills confidence from the buyer's point of view.  Plus as a buyer I know it's always nice to have a seller respond quickly.  It tells me that this person is supportive and interested in what happens to their auctions.

When it comes to actually answering their question, try to be as thorough as possible.  If it's a question about shipping costs these can be quite straight forward.  However if it's a question about the history of an item or it's condition etc. try and be concise, but make sure you have answered their question fully.  Also, don't be afraid to put in a few choice adjectives.  Remember this is a good opportunity for you to really sell the item.

Another important point is to try and anticipate other or future questions the person may be having.  If they're asking about the condition of your item, you should also maybe mention the condition of the accessories it comes with (ideally this should be done in the item description).  If this information is in your item description you should assume that the buyer is looking for a more detailed answer.  For example describing something as "like new" is quite vague and begs for more detail to be added.

Finally, remember that when someone buys something, they're buying an item but they're also buying the seller.  Remember that in any communication with a potential buyer you want to come across as supportive, helpful and honest.  You should think of buyer questions as an opportunity for you to demonstrate that you are the seller they're looking for.

Best of luck!