Art Show - Auctioneer
It helps to find a good auctioneer. Depending how big your auction is, you may want more than one. Stick with one for under 30 pieces. You want more than one auctioneer for over 100 pieces. Between those limits, it would depend on how many good auctioneers you have and on their preferences. Remember that the best auctioneer is the one who can get the highest prices within the allotted time. This may not be the most entertaining auctioneer. High prices plus entertainment is better than high prices alone, but high prices without entertainment is better than average prices with entertainment. Particularly for larger auctions, the auctioneer needs to be good at controlling pacing and intensity (for most auctions, you should be running 25-40 pieces per hour. Faster or slower will lower the prices (slower probably more than faster)). Your auctioneers also need clear and understandable speaking voices, and it helps if they know the art.
Being a good auctioneer is a skill unto itself. You have to keep track of the art, the bidders, the audience, and the time simultaneously. There are many styles (e.g., check out the game auctions at the big gaming cons sometime). Not all auctioneers will work together comfortably. If you will have more than one, pick some who can work together well.
In some states, auctioneers must be legally registered. This is basically a cartel law - to become a registered auctioneer requires fees, exams, attending an auction school or apprenticing for a registered auction firm (state laws vary). Check your own state's requirements - requirements for registered auctioneers may be waived for nonprofit orgnaizations, or may not apply to your particular type of auction. States with such restrictions include: Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Mississippi, North Carolina, Ohio, South Carolina, Tennessee, Texas, Virginia, West Virginia, and Wisconsin. I have no knowledge of Canadian law on this subject - anyone?