How do collectors establish relationships with auction houses?

The direct way is usually the easiest way. That is: buy and sell art.

What happens to the royal family's old stuff? Do they auction it off or sell it to museums? - Quora

What is the record for the highest selling price of a camera at an auction house like Sotheby's or Christie's? - Quora

What is the record for the highest selling price of a camera at an auction house like Sotheby's or Christie's? - Quora

I am downsizing our personal Hollywood collection, with a rare film print just found of 'This is Cinerama'. How do I confirm and value it for auction? - Quora

What is the best way to establish a relationship with an auction house? - Quora

When should I use online auctions? - Quora

What is the record for the highest selling price of a camera at an auction house like Sotheby's or Christie's? - Quora

What happens to the royal family's old stuff? Do they auction it off or sell it to museums? - Quora

How do auction houses work? - Quora

Why do people buy celebrity garbage/trash/throwaways at auction? - Quora

Why do some of the most savvy collectors in the whiskey industry turn to auctions such as those held by Sotheby's to build out their own shelves? - Quora