Hi,
1. Always list a few pictures. People are generally not willing to pay very much for an item they can't see.
2. Before you sell something expensive, you might try selling a few other items and build a little feedback. Unless you have some feedback now with items you purchased. People generally don't like to bid on an expensive item from someone with no, or little, feedback.
3. If you're really worried about payment you can select an option that says you only accept money orders or cashiers checks. State in your auction that item will ship when check has cleared your bank. This usually takes 3 days at most banks. Paypal is generally safe but I don't know what their ability is to debit your account if for some reason the buyer claims fraud.
4. I've found that people usually don't bid on an item that has a high reserve however, if you've got very little feedback then you might want to consider a minimum selling price for the watch. Set the starting bid at that price.
5. You can list in your auction that you will not sell to anyone with negative, or no, feedback. You can also cancel those bids during the auction. I had one guy with no feedback outbid a few people with lots of feedback for an item then he didn't pay. I relisted the item and it sold for a lot less than it would have if the deadbeat bidder had not been a part of the auction. So state you reserve the right to cancel bids and if you've got what appears to be a couple of good bidders that keep getting outbid by a person with no feedback, you can cancel that persons bid.
6. Generally the biggest nuisance I've faced is a non-paying bidder. Ebay refunds the listing fees AFTER you re-list it and sell the item. Still kind of a pain and a waste of time.
Overall, I've haven't gotten ripped off selling anything to date and have a general positive experience with buying and selling.