Talking by the both short and the long descriptions on a story, what are the top priority things we (I, for one.) should add to both inform the reader about the story and make him/her interested in the story? And of course to do this without spoiling it.

I'd like to know this as well.
I used a semi-out of context quote from the main character as a hook, sort of like how you can start off a chapter, but, uh... I dunno, I want to avoid too much "back of the DVD" language.

The basic plot I guess... Give them something that would give them a good idea on how the story is going to be like. The beginning of the story would be a good start, maybe a bit of the middle, but never the end.

Who is the star of the story? What is she doing, or what situation is she reacting to? What conflict (if any) is present, and what are the stakes? Are there any elements some readers might enjoy or want to avoid? (Anthro, human, clop, violence, etc.)

Just some ideas off the top of my head...

933068
When it comes to descriptions, I like to refer to this blog post - there's a section Description in there, pointing out that the most important things are: WHAT your story is about, WHO is in your story, WHY it is unique and worth the reader’s time.

For the full summary: Give the character and history that they come from, and say what they plan to do or what conflict (not a full reveal) is tossed into play.
For the short summary: Name the character, maybe a quick thing of their past, enter plan/conflict/etc.
This is what I personally do.

Example from He Who Loves Nightmares:
A thousand years ago, Princess Luna went mad with jealousy. Her only lover cast a prophecy for her return. A thousand years have passed and he has made the preparations. Her return is nigh. Will he be able to return Nightmare Moon to his dream Luna? Or will Celestia and her Bearers use the Elements of Harmony on her again?

Dage, Luna's only lover. He has waited for her return, but will Celestia foil his plans?

Also to be noted, I have a norm of having series being noted in Italics before the summary and then a discalimer about rating and content (better than the rating system can do) below, again in Italics. The Italics make it clear it's not the summary, but it still provides the info in case they find later parts of a series or they don't like language, violence, etc in their stories.

The plot, the stakes, and enough to entice the reader to look inside.

The description is pretty much advertising; as long as you don't lie about the contents of your story (ala Dipper Goes to Taco Bell) your goal is to get people to read

Think about hooks in your story. You're trying to sell your story, metaphorically speaking, to the reader. So think about why you think someone would want to read your story. Set it up so that you tell them why they're going to read it, basically. But try not to be dull with it, try to make it sound interesting.

933068

Descriptions are adverts.

Seeing reveal trailers for films / games tells me:

1. What the film is about
2. Who is it about
3. What the stakes are (what the protagonists stand to lose and gain)

And things like the tone of the story.

Writing descriptions is quite difficult, actually. Another way is to look at some of the descriptions of the feature-box fics, and find out why they attract you if they did.

Explain a little about the story. Maybe describe the events of the first chapter or so.

I'm not sure (so don't trust me on this) but I'd say describe things as they become relevant in the story, don't just go into describing as much as you can to start off with. When you enter a room for the first time do you notice the color of the lampshade in the corner instantly? No, of course not, you notice it when you go to turn the lamp off. I'm not saying that people should leave out any description at the start of a scene (you still notice some features when you enter a room for the first time) but, unless you have a good reason, try to keep that description to around 2 paragraphs or less maybe?

Of course, at the start of a story you need to go into the characters; the what the place looks like and the general plot as well as giving readers a general feel for your story so a bulkier description would probably go here though I personally wouldn't go for describing things like character personalities (like 'x was a happy kind of pony') because I think the reader should be able to work that kind of thing out on their own from how the character is feeling and what they say etc.

Edit: Ignore all that, completely forgot about the description box... well... at least you got a good tangent out of it!

One thing I'd suggest: avoid asking lot of questions. You want to give a short, firm reason for your reader to come into the story and asking lots of questions usually sabotages that by making your description seem mealy-mouthed and unsure of itself. Generally the more wordy your description, the less likely it is to work. Questions add a lot of words.

Be short and to the poin The best short description I've ever seen was given to me by FanOfMostEverything for one of my fics.

Calamity befalls the royalty of Equestria and, in lieu of plans that took decades to create and moments to ruin, control of the cosmos is bequeathed to the only pony Celestia had time to empower.

It says everything you need to know in a single sentence. The plot is set in motion, the stakes are made clear, and it entices the reader with a mystery: just who is that pony? It's a question doesn't need to be asked because it's implicit in the description itself.

The best suggestion I can think of is to go and listen to a lot of movie trailers.

933068 One thing I read (can't recall what or where it was) was give three pieces of information in one sentence at any one time. Visual description, then the viewer's impressions. From what I remember, three is the most (or optimum) a sentence should carry, and all the reader will pay attention to before you lose them.
Something like, "He was a tall, broad Swede with bright-blue eyes."

Ah, yes. I believe I can shed some light on this. In both short and long descriptions, depict the issue as vaguely, and as grippingly as possible. It helps to mention a fact of life that gets on peoples nerves, makes them laugh, makes them nervous, or just makes them downright go 'Holy s**t man...'

To clarify, the issue is the meat of the story. Try to avoid spoiling your plot in descriptions and lure us in with the issue.

Craine...

933068 A good Long Description (in published literature, movies, etc.) generally introduces the main character and gives a brief glance at the conflict. It isn't too specific in details, but gives a type of premise that will help potential readers decide if the tale is worth the time to start.

The short description is the same as the long, only condensed into even smaller glances at the conflict.

If your description is

It was science that saved the world. It was science that he loved. It was science that everyone studied. But when Wits Lucid is the victim of an experimental procedure, he’s led down a path that threatens to tear his mind apart. Not only does his own personal sanctuary start to betray him, but he’s cast out into a world ravaged by war and time. Faced with the challenge of overcoming both his own illusions and the wasteland horrors around him, he must find a way to fix the fragments of his mind…and maybe help the wasteland while he’s at it.

then a suitable short description would go something like

After an experimental procedure goes wrong and he's cast out into the wastes of the world, Wits Lucid has to battle against his own mind in the hopes of putting the fragments back in place.

What if I had a story were I cannot absolutely, spoil the main conflict because the moment it appears the story turns 180º and becomes completely different?

Like, say, a story about how Twilight researches a new spell language that allows for more efficient magic but after it is used for low cost magic for prosperity it is revealed that it's draining nature's life force.
The first part needs exposition and an interesting one but knowing that in the end things are going down the shitter, well, it becomes pointless; but if you don't do it it just loses the impact the reveal would have and you end with the half of a story.

Descriptions are tricky. If you have too much/many then you lose the reader 'casue the story doesn't move. Except if there are too few and the reader doesn't have enough to paint a picture in their heads.

As for an explaination of what is going on, that kinda depends. There are many stories that leave it out until you really get into it, before you get the back story. Many more that create a Prologue, the background at the very begining. Still others explain it slowly, giving the reader in bits and pieces, not necessarily in chronological order. Lastly, some authors put the background story until nearly the end.

...as little as possible. Tell the whole premise of the story in a very short efficient sentence or two. It has to be long enough to let the potential readers get the jist of the story. If it's too short, or too vague (see Austreoh) you'll turn away many potential readers because they won't want to invest time in a story they don't know anything about. Make it too long and descriptive and they'll know the whole story before even reading it, and they won't have any curiosity as to what the story could be.

935547

This. The key is to tell the premise; telling any more is just a spoiler!

935547>>935730

I sort of disagree here. The most important thing to put in the description is the most interesting thing about your story, or failing that (due to spoiler reasons), to convince the reader that there is a most interesting thing about your story. The key is to get their interest, and the premise alone may not be sufficient, because not all stories have the most interesting thing in the premise.

935788 Seems legit.

935788

True. I believe a good story starts with a good premise, so I guess the sweet spot would be a blend of our perspectives. Just stating the premise (Lyra/Bon-Bon story!) won't turn heads; trying to claim "It's a Lyra/Bon-Bon story with a twist!" is just trying too hard and won't turn heads either.

But if you describe the premise in a way that shows off your unique, interesting take on it - "Lyra/Bon-Bon shotgun wedding after a 'help-mares-have-legit-foals-spell' contract is breached" - you've at least come across as interesting. Show, don't tell. Don't state that it's interesting; state it in such a way that makes the reader decide it's interesting.

Basically, an attention getter.

Giving a description of the plot is merely part of the cover, the other half a reason the audience could find interest or relevance to the story.

935868

It depends on the story. For a story where the premise is where the interesting thing is, then it's ok for the description to deal with the premise alone, but that's not always the case.

I'll try to give an example, but it's pretty late so my head might not be working too well:

Example A: "On a shimmering morning in Ponyville, Applejack's body is discovered with a sword through the heart. As Twilight Sparkle and her friends search for the killer, the chains of clues left behind lead them across Equestria into strange places they could never have imagined."

Example B: "On a shimmering morning in Ponyville, Applejack's body is discovered with a sword through the heart. As Twilight Sparkle and her friends search for the killer, the chains of clues left behind lead them across Equestria into strange places they could never have imagined. And yet at the mystery's heart is a shattered mirror through which Twilight must look into her own depths, to find the most unlikeliest of killers..."

A gives a premise only, whereas B gives the premise with the promise of a unique take on the murderer, while leaving the details vague enough so as to make anything possible (sure, it hints that Twilight's the killer, but that could easily just be a red herring).

933068
People say my descriptions are pretty good, (really trying not to self promote, just going to analyze what I did, which feels wierd btw)
-----------Short one:
A blend of the high octane action and off-the-wall characters of Panty and Stocking with Garterbelt and...My Little Pony!? Oh Boy...
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Right with the first couple words I've given the style (Action) and the type of characters (exaggerated) and immediately given the context: its a crossover fic, I've also given what I'm crossing over with. I could have done more, but I left that for the longer description

-----------Long one
Twilight Sparkle has been kicked out of Canterlot because she spends all her time studying...and because Celestia is a bitch. Waking up in a strange city that lies on the fault line between the Everfree and Equestria, Twilight has been given a task to complete if she is to be allowed to return home: rid the town of the Beasts that are threatening to destroy it and stop the evil sorceress controlling them, Lady Nightmare. Twilight can't do it alone but the only people she can count on is a crass hick, a neurotic shut-in, an overzealous diva, a reckless braggart, and a trigger-happy psycho!

This is a Panty & Stocking crossover persay. In that it's My Little Pony, if it was in a Panty & Stocking universe, but you don't have to get the context to like it, I made sure of that.

(I'm warning you right now there are going to be completely out of context crazy genre shifts)
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With the first line I established the style of humor that was going to be used, and the basic premise, so that it can be easily recognizable. The secondary description of the exaggerations of the other characters helps reinforce the humor and I also snuck in the conflict of the story. There's plenty there but just enough to explain and entice
I know some people say that they hate the "Back of the DVD" description, but I think that's just because most often they are reading the bad ones, a description needs to give you everything your getting into, without telling you everything.
Pretty basic right?

The secondary bits where just warnings, a courtesy for the readers,

A description for an unpublished story mentioned something that will be touched on at the end of the first chapter and throughout the story. But I felt it revealed too much about the sub-plot and limit guessing that could arise from it. So I cut it out and plan to have the story tell people about it.