Creative Writing.. Please read :)

Okay so basically it's just a short piece between two characters, 250-350 words. It's gotta be about an incident... and this is pretty much what I wrote. I need to use a simile, metaphor or personification effectively, as well as assonance, alliteration or onomatopoeia, and I need to appeal to different senses (Sight, sound, taste, touch, or smell), use show not tell, the character needs to be shown through gestures, body language, and through dialogue also. I also need to use varied sentence lengths, use effective verbs and finally, have interesting vocabulary. Please please tell me if I can improve on any of this, or pretty much make it of Excellence quality. Thanks for reading

--An eerie mist covered the city, veiling itself in a mysterious shroud of grey. The city seemed cold and empty, tall buildings looming like skeletons over the labyrinth of streets below.

A cruel wind blew through; a bitter voice breaking the silence. "Did you see him fall?" No response. "Did you see anything?" The girl looked up at the man, fierce, big brown orbs reflecting his morbid curiosity.
"I didn't see anything," The pair stood quietly for a moment, their clothes beginning to dampen by the falling rain.
"He's dead." The girl exhaled, her brows drawn tight in thought. The boy between them was unmoving, a halo of blood around his head.
"Did he kill himself?" She asked, her voice wavering slightly.
"Not sure," He replied, regarding the girl's glass composure. The man's face was grim. Sirens wailed anxiously in the distance, help was arriving shortly. He looked at the girl sympathetically, and said softly, "Jack. I'm Jack." There was a pause, a moment's heart-beat.
"I wonder why," She whispered, "I wonder why did he do it? What was so bad?" She bent down to examine the boy closer, her tentative hand brushing over his cheek. He was only her age, just a kid making his way in life. Now he was gone. The girl stood up, her eyes slid back over to the man. "Leah, I'm Leah," She hesitated. "It's sad really,"
"Yeah?"
"Yeah... Mum'll be so sad he's gone."

The ambulance came to a screeching halt beside them. And the boy was carried away in a sea of hands.

Hi

First off, you should put your author's note in a spoiler so that we know when your actual piece begins and so that your note does not detract from your work.

On to the review:

An eerie mist covered the city, veiling itself it in a mysterious shroud of grey. The city seemed cold and empty, tall buildings looming like skeletons over the labyrinth of streets below.

The first sentence means that the mist is covering itself in a grey shroud. I think you wanted to convey the city being cover by the shroud. By deleting "itself" pertaining to the mist, and replacing it with "it" (the "it" in this case belongs to the city) allows the city to be covered in the shroud.

In the second sentence you are trying to compare skeletons to tall buildings. How are buildings like skeletons? If you had said, "The buildings loomed tall and ancient, like the cliffs of Dover" then you would be making a correct simile.

A cruel wind blew through; a bitter voice breaking the silence. "Did you see him fall?" No response. "Did you see anything?" The girl looked up at the man, fierce, big brown orbs reflecting his morbid curiosity.

Are you trying to say that the voice was a bitter cruel wind? If not, these two descriptions should be separate sentences, or there should be a conjunction like "and". For example, "A cruel wind bit at the skin of the man, and he broke the silence with a voice dripping with bitterness".

The last part doesn't really make sense either. How can his morbid curiosity be reflected in her eyes?

"Did he kill himself?" She asked, her voice wavering slightly.
"Not sure," He replied, regarding the girl's glass composure.

First you say that her voice is shaking, and then you say she has a steady composure. Which does she have?

Sirens wailed anxiously in the distance, help was arriving shortly.

The comma in this sentence should be a semi-colon, ";".

He looked at the girl sympathetically, and said softly, "Jack. I'm Jack."

This came out of nowhere. I really thought that the man and girl knew each other. It also isn't really clear that he's introducing himself to the girl. At first I thought that he was reading something off the boy's clothes, or telling the corpse his name in a gesture of respect.

The girl stood up, her eyes slid back over to the man. "Leah, I'm Leah,"

And her reply is way too delayed here. I think you should rearrange this to be come:

"Leah, I'm Leah. I wonder why," She she whispered, "I wonder why did he do it? What was so bad?" She bent down to examine the boy closer, her tentative hand brushing over his cheek. He was only her age, just a kid making his way in life. Now he was gone. The girl stood up, her eyes slid back over to the man. She hesitated before saying,. "It's sad really,."

"Yeah?"
"Yeah... Mum'll be so sad he's gone."

I don't think a man would say, "Yeah?" after hearing that. A real man would say something like, "Of course it's sad", or "Why?" at the worst. Also the sudden revelation that Leah knew the boy as a brother, but showed no emotion upon learning of his death is questionable.

The ambulance came to a screeching halt beside them. And the boy was carried away in a sea of hands.

Who called the ambulance?

Okay, let us run through your list of things you need to achieve:

simile, metaphor or personification effectively
Okay, you failed a tad with your use of a simile. If you could touch up on your skeleton building sentence, this criteria checkpoint would be reached. You used a metaphor with "glass composure", but in doing so created a contradiction, so you might like to go back over that.

assonance, alliteration or onomatopoeia
I could actually find no assonance, alliteration or onomatopoeia in this text, so you might want to go over that (of course I could have missed something). An easy way to introduce some onomatopoeia would be to describe a sound occurring through an action. For example, "Bees buzzed by", which is an example of alliteration as well.

different senses (sight, sound, taste, touch, or smell)
You have sight and touch down and you mention sound, but you could write something about the coppery smell of blood, or the smell of the decaying debris of the alleyway. Understandably you wouldn't want to describe tasting the blood

show not tell
I've always been bad at this one, but I believe you did a good job of showing what happened.

the character needs to be shown through gestures, body language, and through dialogue
I think you achieved this quite well

varied sentence lengths
I believe you could work on this one a bit more by expanding some of your sentences to make them longer. You have plenty of short sentences, but not very many long ones.

effective verb usage
Yup.

interesting vocabulary
Here I think you could improve upon. Have a look at some of the words in your story that could be changed. This:

The city seemed cold and empty

Could become, "The metropolis seemed achingly bleak and bereft of life".

Hope this review helped

- Jai

Hi, jenth here
Hmm, Leah refers here Mum, so I'm guessing that she's related to the dead guy. However, she's clearly unperturbed at his death and the 'halo of blood' (nice words, there). I think you should give her a deeper emotions, because I would be running around screaming in her position.
Now, another thing is how they introduce themselves to each other. Both use the same format (Jack, I'm Jack. Leah, I'm Leah) so that's repetitive. Also, it's a very bland and dull way to go about things.
Try to understand what feeling you want each of your characters to have. This feeling will be like an aura around them, affecting other characters and affected by other character's auras.
I say you give Jack a affectionate aura, almost a fatherly feeling. His compassion reacts to Leah's sorrow (which you need to bring out more) and grief. Dead guy has an aura too, or he should.

Anyways, when working with characters, remember that they're not islands, separate and taciturn entities aloof from all emotion. Have them work on each other and react accordingly.

One last point...make it longer. As is, there isn't much of a story to it. What happens afterward? Do they ever find out if he was suicidal? Questions, so many questions...
...
I just noticed now that you posted this in nonfiction. O_o

*ahem*
~Jenth