User Activity

I listed my items as Auction but now I want to revise it for fix price but it is not letting me to change. is this possible if you see that bids are not doing justice with the price you want to set a fix price.
Hi I am a new ebay member have lots of stuff of almost every categories to sell but bit confuse how to target a particular market to sell the things sooner.what are tips and precautions we should use to attarct buyers?
How ebay select our item to list at specific page? How our Add can be placed at the top when it is new? Is any order number criteria?
Just want to know how long we can place one item for sale? what happen if it is sitting on ebay has not been viewed by any one?