Writing ...

Hi all,

I desperately want to improve my writing skills and it would be nice if someone could correct my mistakes:

"Going once, twice, SOLD for $21.000 to the gentlemen in the back," the auctioneer shout in his microphone.
He took a sip of his sage tea and swiftly moved to the next object. "And the next item up for bid is a painting by the young artist", he said in a monotonic voice. "The painting is 16 inches by 20 inches in height. It is painted in oil on canvas, and not framed."
His assistant uncovered the painting and held it up for the bidder to
see. It was an abstract painting, just lines and shapes of color but with some imagination you could see a woman in a blue dress.
"Who'll start me out at $15.000?" With these words, the auctioneer starts the auction.
Someone raised a hand but a few seconds later an elder woman bits $16.000, and then the woman right behind her $17.000.
It went on like this until the price reached $28.500 then the bidding halted for the first time.
"I have $28.500 and who'll give me $29.000?" the auctioneer said, searching the crowd for another bidder.
"$50.000," a boy who was on the phone called out and a murmur went through the saleroom.
"$51.000," another bidder yelled. Everyone in the room turned to look at the new bidder. It was an elder man with glasses, and the lights in the room reflected off the bald spot in his gray hair.
"$60.000," the boy on the phone yelled again.
Everyone in the room looked at the older man with a surprised look. "$70.000," he finally said, and the moaning in the room was getting louder.
The bidder on the phone increased the offer price to $80.000 and the man in the saleroom immediately offered $100.000 for the painting.
"$120.000," the boy on the phone called out repeating the word the person on the other side on the phone had said.
By now there was dead silence in the room, and all eyes were on the gray-haired man. He shook his head slightly.
The auctioneer watched the gray-haired man for a few seconds before he finally said: "$120.000 going once, twice," he stopped speaking, watching all bidders, then continued: "SOLD." The auctioneer slammed the hammer.

Thank you!