I have lots of eperience with selling phones on ebay, here's a few tips:
if you must use the auction listing, make sure you cancel stupdly high bids as soon as you spot them
look at what other people have sold the same item for in the past, so you know what bids are likely to be genuine
remember, feedback isn't always as it seems, if someone has 40 positives 100% for 1p ebooks, its nothing, if someone has bought 5 Ford Escort parts, playstation games, and a rabbit cage with normal prices, thats proper feedback
I always use buy it now listings, and require immediate payment, that way, the item doesn't sell until the money is in my paypal account
POSTAGE - use a trackable service, and keep the details, paypal and ebay get plenty of bad feedback, but if you are careful, you can't lose out
Any questions, feel free to ask