1. Irony: Verbal, Situational, Dramatic

2. Verbal Irony
An attitude or expression that is opposite of what is said.
Example of Verbal Irony:
You get into a wreck and the passenger says, “You’re a great driver!”

3. Situational Irony
When a situation or event ends the opposite of what is expected
Example:
When a lifeguard is saved from drowning…

4. Dramatic Irony
When the audience knows something that the characters do not…
Example:
Horror films are notorious for presenting dramatic irony. The audience always knows where the bad guy is hiding when the “frantic” girl does not.

5. Applying Irony to “Twilight”
Dramatic Irony:
She wants to know how he tracked her in Port Angelo. He says, "Your scent." She doesn't know what to make of that, but the reader knows that he's telling the truth.
Verbal Irony: Bella: "How long have you been 17?”
Edward:  "A while." 
This is verbal irony since he says one thing (a while) which usually is a few hours, days, months, or years, but he actually means a few hundred years.
Situational Irony:
Most audiences felt that Bella would be afraid of Edward Cullen after discovering he was a vampire, not drawn to him.