to avoid the problem Theo mentions, ie being lost in the noise on ebay, you will want to make your ad look as professional as possible, with lots of pictures. and good copy.
The things I think are important in a do it yourself transaction are that at least one of the parties needs to know what they are doing, otherwise its the blind leading the blind. and you have to trust each other. If you dont know the other party thats difficult, so I recommend a third party to handle the deed prep and recording . and an escrow company if there is any money involved.