This is something I decided to do one day to try and help out anybody who's writing, or just to give somebody something to waste a few minutes on. Anywho, onto the list, I say!
1). Be creative. This is the most important aspect in fiction that many authors today are ignoring. Somtimes the most creative, successful ideas are the most random ones. For instance, you might be playing COD (or some other overrated game) and might wonder, what would happen if I gave a knight back in mideivil times this bazooka I'm using? Or, what would happen if I had super strength and I threw this apple I'm eating all the way to China and killed somebody? Then thought builds apon thought and just like that, you have a rough plot! Again, it doesn't have to make sense right away, just as long as you have the general idea.
2). Be unique. I cannot stress this enough: BE. UNIQUE. Come up with your own story and your own characters. (This kind of ties in with Rule 1.) Another very important aspect. For an example, ever since Twilight came out there's been countless vampire story after vampire story, all because one got really famous. Don't do that, make an entirely new story with new outcomes, characters and the whole shebang. While this sounds deceptively simple, it can be really hard not to base a character on some badass from Final Fantasy or a setting from The Lord of the Rings.
3). Use details. I know they aren't appropriate in places and a crapload of them can be agonizing, but details can paint pictures of what you're trying to describe in readers' heads. I know people today don't much like reading the extra fluff, they'd rather read how the protagonist whipped the antagonist's ass in an epic fight rather than what either one or where they're fighting looked like, but it doesn't even have to be physical traits. Stuff like the character popping his knuckles nervously or flicking her hair out of her eyes all the time can do wonders for the character's personality. So remember, use details unless this excites you: I escaped the trap. I found Dr. Douchebag. We fought, I won, the end. Woot.
*However, on a side note, don't use fancy substitutes for the word 'said', like 'he admonished gravely.' 'Said' gets your point across and it keeps your readers from going "What the hell...." and getting out the dictionary.
4). The ending doesn't always have to be good. Sure, everyone likes a good ending, the damsel's rescued, bad guy loses, the end, but bad (or even nuetral) endings can really be a twist. For example, if you've ever seen the movie 'Knowing', it has one of these endings, and Stephen King's 'Insomnia' had one as well. What you don't want to do, however, is make a dissatisfying ending, such as it feels like it ended too soon, unless you're planning on making a sequel.
5). Along the same lines as Rule 4, try to include twists that keep the reader wanting to read, i.e. build suspense. This doesn't mean the character has to be in constant danger, but try to keep the readers interested in whether or not the hero(s) will defeat the antagonist and/or will maintain their goal. If the hero always gets away from the villain and always wins, there isn't any appeal to that. People want to read about the challenges the hero(s) face, not how the hero(s) always kicks the villains ass and does it one last time at the end. It also helps if you give the hero(s) traits that readers can sympathize with. Dean Koontz's 'Intensity' does an amazing job of building suspense.
6). Simple plots are good and well, but complex plots can be, too, if you know how to handle them. The series I'm writing has an immensely complex plot- it'll take 24 books and two series to finally said what needs to be said- and I find it gives your characters a lot more options to choose from other than 'beat the villain, save the day'. However, this can be detremental if you don't keep your facts straight throughout the entire process. For example, how did Bob defeat Joe in the fifth book if Bob died in the end of the third? and so on. So the main thing to remember is make sure you know your novel's (or series's) timeline and all the characters in it.
7). Don't use hollow villains. Villains without some sort of backstory are shallow and leave the readers wondering why they're evil. Don't use cliche reasons, either, such as insanity, or any other mental disease. I find these are excessively overrused and are way too easy for the author to implement, because the villain's only motives are 'they're insane'. Even the 'they had a rough childhood' is better than that. Also, avoid making villains totally evil; you want the readers to identify with them, but not so much that they like them better than the hero.
8). Some writers can write about any personality, but I find it helps if the main character (the one you're mainly writing about) reflects your personality. It doesn't have to be exactly the same, but it makes things a whole lot easier than writing about a character that's just not you. An example would be in one of my books (that I eventually scrapped) I was writing from the villain's perspective, which was incredibly hard to do because his morals and outlook weren't mine at all, and I found it really hard to 'get into character'. Secondary characters aren't that bad, because you don't center around them so much.
Well, that about wraps it up. Hope this helps anybody ^^