Ebay is always the best. Whatever you are selling, make sure to see if other people are also selling it as well. You don't want other sellers selling the same thing you are trying to sell, and not have it ultimately sell. You can also look through closed auctions of whatever you are selling when doing a search to see what it sold for.
If you do end up selling on ebay, just make sure your minimum bid isn't way overpriced. You don't want to not have it sell. And, always have the buyers pay for the postage/shipping of the item.
Do you have any really rare items? What type of pieces do you have?