Title: 2/5
There’s nothing that stands out about your title.  Titles should catch the attention of the reader, but yours is too broad.  Also, it doesn’t seem to have any connection to the story, but it’s too early to tell.

Description/Foreword: 4/10
Character descriptions are a big no-no when it comes to writing.  You’ve basically given away all of the necessary information to me in a few short paragraphs.  I didn’t read the character descriptions because I hoped that you would incorporate that information into your story.

As for your foreword, that one quote has no relevance to the story so far.  Forewords should include either why you decided to write this story--like an author’s note, or you show the readers a sneak peek of what’s to come ahead.

Poster/Background: 10/10
The blending is a bit awkward, but overall, it’s a nice poster.

Characterization: 6/15
Your characters have no depth to them.  What that means is that they don’t seem like real people.  When characters feel alive--when I can imagine characters shopping at a supermarket--then that’s when I know that characterization was done correctly.
The characters are flat and boring, honestly.  Write your characters out like they’re real people, and not just some random OC that you came up with.

Spelling/Grammar: 9/20
You have tense errors, but your spelling in general was great.  

Quick English lesson: There’s past, present, and future tenses in English.  I, personally, prefer to write in past tense (ran, jumped, swam, ate, etc.), but there are many writers that like to write in present tense (run, jump, swim, eat, etc.).  Whatever tense you choose, stick to it.  Don’t go around mixing tenses because that will lead to confusion.


And I don’t think you’d refer to JYP as a sunbae...he’s more of a CEO than a sunbae.  Same goes for Yang Hyun Suk.

Flow: 3/10
Your order of events is flawed.  
You mention first that Seol and Sooni are trying out for the 2009 JYP Audition.  Then you mention that they both sing a song from Dream High 2, which premiered in 2012.  See where I’m going with this?  You can’t sing a song from 2012 in a 2009 audition because it didn’t happen yet.
Nine months pass, so at latest, it will be September of 2010 when Sooni is about to debut.  
When Seol meets TOP in Park Han Byul’s store, he says he just came back from New York.  Assuming that he came back because he filmed the music videos, you’re still in the wrong year.  Get your events straight first, and more things will fall into place.

Originality/Plot: 10/25
The plot is hard to decipher from five chapters, which can be a good thing and a bad thing.  It’s good because five chapters isn’t supposed to give away the whole plot.  It’s bad, though, because there is no indication of where the plot is going.  You could’ve brought out the possible hardships Seol went through during her trainee period--you skipped over that part.  You could’ve brought out many interesting things, but you chose not to.

Enjoyment: 3/5
It wasn’t something particularly enjoyable, but it was satisfactory.

Total: 47/100

General Comments:
Have you considered requesting for a co-author/beta reader for this story?  Both can help you with English, and both can help you with improving your writing.  No writing is perfect, and you can learn from almost anyone you ask.  Of course, everyone has their different opinions, but the end result is the same--becoming a better writer.  Thank you for requesting a review, and sorry if this wasn’t the score you were hoping for.