I've found through study and analysis, a boom comes from two things:
1. Speculation 2. Demand
First things first. People speculate that something will go higher in value. Hence people want it. Then the next guy says hey, look at that, he made a bundle of money. Then so on, and so on...
Sorry for the vague explanation. Let me give you an example.
Ronny has a baseball card of mickey mantle, let's just call him mick. Ronny bought the card at 50 cents.
Joe is sold the card for $0.75.
Tim sees how Ronny made $0.25.
Joe tells Tim the price is bound to go higher and that is why he bought it.
Tim wants in on the action so Tim buys the card of the mick for $1.
Ronny realizes he could have sold his card for more.
Ronny buys the card back at $1.25.
Matt sees how much money everybody has made.
Matt is convinced the price will go higher.
Ronny sells it to him for $1.50
Matt buys the card.
Greg buys the card for $2.00, quite a jump.
Everyone sees how much money has been made on this card.
All the school yard kids want in on it.
They make an offer, each higher than the last.
Finally the card goes up to $10.
Ethan is left holding the $10.
Ethan looks for a buyer.
Nobody wants to buy it for him.
Ethan realizes he bought the mick at a high price.
Ethan lowers the price and tries to sell it to Jane.
Jane does not want to buy it.
Ethan decides to sell the card for $8.
Still nobody wants to buy it.
Other kids who have the Mick begin to realize how they have wasted their money.
They sell their cards.
Everyone in a frenzy begins selling it.
Now nobody wants it.
The price is below the 50 cent buying price.
It is now worth 10 cents.
THAT IS HOW A BOOM AND BUST WORKS.
"I want money, I buy high, I sell high."
Eventually the last man holding loses out. So avoid the hype!
You make money at the end of boom, or the bust.
Buy in the bust, and then sell again in the next boom!