More items does not always mean more money raised! Mind the following when deciding which items to include in your auction:
Most online auctions have between 20 and 40 items, though an auction with 12 or so great items can be very successful.
It is better to have fewer items that are all high quality vs. many items of varying quality.
At an absolute maximum, include no more than one item for every two bidders.
Bundle lesser value items together to make a great item.
Look to sell multiples of the same item.