Nowdays, the buyer is fairly well protected against rip offs, so a new seller is really a non-issue, however there are probably still a number of vets who shy away from newbie sellers. The demand is driven by the items for the most part. If you are selling the same thing 1000 other guys have, then you will probably get less interest than the seller with 1000 feedback selling the same thing. Good stuff gets found and purchased for decent money most of the time. Junk sits stagnant or sells for cheap.
As a buyer, I really like items that start at 99 cents. Even if I know the item will top $100, it gives me hope that I may get a bargain and stimulates bidding. I have passed on items at fixed prices and actually bid higher in auction format. It doesn't happen often, but the heat of the battle makes people do strange things. However, you always run the risk of getting less than you wanted. I also hate reserve prices. Reserves usually tell me the seller wants more than the item would sell for anyway, so I rarely even bother to bid when I see a reserve set.
I'd suggest starting slow, establishing a reputation with buyers. Offer fair shipping rates and be clear about your combined discounts. Some would stay to shy away from buyers outside the US. That is a personal call. Often there is extra hassle, but the more of an audience you exclude, the harder you need to work to sell. I'd plan on using insurance on anything you don't want to lose. It's probably worth the price for the added protection. As I said earlier, the buyers are well protected these days, but this has exposed honest sellers to more risk. Paypal often sides with the buyer, so that is why I suggest tracking and insurance. Even then, you run the risk of someone paying, receiving their item and then falsely filing a claim.
Ship in a timely manner. If you are the guy who can only go to the PO every other Friday, expect poor ratings for shipping. Go the extra mile to protect and package items properly. Holders, taping or sealing items in bags, using cardboard backers, etc is all very much appreciated by buyers who fully expect the item to arrive as advertised and don't care if you try to blame the PO for mishandling. In the end, the seller will still lose that battle!
If you can follow those guidelines, you should have a successful experience selling.
I don't sell, but I buy a lot, so my perspective is that of a buyer.
