2. Choose the Best Form

Disdain came off her like a perfume.

The final step is finding a format for your metaphorical. A natural (and unthinking) choice is the standard form for a simile, like the above. And occasionally that's the best choice.

There are many more possibilities.

She wears her disdain the way other women wear perfume.

Wears is a lexaphor, which I will talk about, and "like" has disappeared. So that's a different format, and an important one to use, and I think better for this metaphorical. But the author chose the amazing:

I could feel her as she stepped closer, a mixture of perfume and disdain that fell around me like ashes. (Hart, The King of Lies)

That has a metaphor-by-conjunction, which I will talk about, and fell has become the lexaphor. Mixture was perhaps needed for clarity, or perhaps heavy-handed. I prefer the lighter, yet more boldly lexaphorical:

I could feel her as she stepped closer, her perfume and disdain falling around me like ashes.

The point is, there is a wide variety of ways to present a metaphorical, and presentation matters. So:

Think about the best presentation.
Learn to use the different choices.

There are a variety of ways of equating two things (other than simply saying one is the other):

Hundreds of voices were shouting over one another in the cafeteria, so that the conversation became mere sound, the rushing of a river over rocks (Turtles All the Way Down, Green, page 2)

The appositive equates sound with the rushing of a river over rocks. The following uses a dash to equate two things:

Many [comments] were inflammatory and a few were horrific – a regular verbal vomit stew. (Here We Lie, DeBoard, page 130)

There are a variety of ways to say that two things are similar but not completely alike (in addition to simply saying they are similar):

Saying it's intellectual curiosity is perhaps the wrong way to put it, but that's sort of what I mean. (Walt, Wangersky, page 61 trade)

The three of them [women] clearly together and overflowing -- that's the easiest way to describe it. (page 171)

Anna Kovacs was nothing more than a crumb to be brushed from his lapel. (Here We Lie, DeBoard, page 132)

The following makes me want to believe the possibilities are endless:

"Excuse me?" Lula said, leaning forward, hands on hips, eyes set in her wild boar on the attack squint. (Evanovich, Explosive Eighteen, page 92)

Something too complicated for me to analyze:

The days were as still as the nights, fertile grounds for haunting by the voices of guilt and regret that had taken refuge in the space where hope and once lived. (The Gene Police, Light, page 89)

This is probaby just too many metaphoricals; it is definitely too many in standard simile format:

He lunged for the stage, grabbing and squeezing like a starving caveman at an all-you-can-eat buffet, then went straight for Kimberly, a tall blone curved like a futurist Italian sculpture. He snatched her right off the stage, tossing her over his shoulder like King Kong. When a waitress protested, he swatted her away like a fly. (The Bouncer, Gordon, page 3)