CharityAuctioneer.com

Silent auction bidders are generally classified as "shoppers".  They are looking for a deal.  Knowing this ahead of time will save you a great deal of stress and confusion over the bids you receive at your silent auction.  

Don't fool yourself into believing, because your organization is really great and everyone in the room loves you, they will throw money at your silent auction.  Average yields in a silent auction is around 60% of Fair Market Value(FMV)

• Don't let your Silent auction become bloated.  A 4:1 Ratio of Attendees to Items is good number.  Saturated marketpalce means noboyd need sto fight over anything and deals are everywhere. 
• Base your opening bid and increments on an items FMV - NOT the Donor Value (which tend to be inflated).
• Avoid allowing increments of less than $5.  If an item won't support a $5 increment, it should likely be packaged, or put in a basket, with other items.
• Never lower prices mid auction.  Once they know you will do this, they will just wait you out every year.
• Most silent items will receive 4-8 bid increases during an auction.
• Bargain shoppers need to be enticed at first glance.  Make certain your opening bid is realistic based on the FMV. Start between 30-50% of FMV.  EXAMPLE:  Item with FMV of $100, starts at $40. 
• Increments are different for each item, but try something in the neighborhood of 10% of the FMV. EXAMPLE: That same item with FMV of $100, starting at $40, can move in $10 increments.

Do some common sense math for an item in the silent.  Take your your proposed opening bid, the chosen increment and the items FMV.  Now take the expected number of bids on an item and see if it seems reasonable to expect it to work out.  

EXAMPLE:  Item with a FMV of $500, opens at $200, with 8 increases of $50 each you are at $600.  It's not the norm to exceed FMV in the Silent, so maybe you lower your increments to $25 so people can get into the bidding.