This is the very first rule of writing stories ever. Applying this rule will improve your story-telling so dramatically, it will be like you were singing in the shower one minute and now you're singing on stage. With Justin Bieber. And One Direction.

I know, I know... your protagonist has a fascinating back story, the kind that would get him through the preliminaries in X-Factor or Britain's Got Talent, no problem. And, yes, it's great that your protagonist's best friend is funny and awesome and they met at nursery and they've been inseperable ever since, but they've never dated because it would be like dating a sibling. But every time you directly tell me these things, you are stabbing your story in its guts and they're spilling all over the screen of my MacBook. Which isn't nice.

The problem is that describing something in detail is a lot harder and takes a lot more effort than just saying, "everyone was sad that the Balrog killed Gandalf, but they just had to man up (plus, they all knew he wasn't really dead, so it was good really because it meant more rations for everyone else)". Guess what? Tough! If you really want to convey how sad it is that Gandalf is (temporarily) dead, you need to describe everyone crying and Sam singing a little song and Aragorn kicking the hobbits with tears in his eyes and snot caking in his moustache.

Like many things in life, the rule itself is simple. Playing by the rules is tough. But if you really want to be an author and meet celebrities who don't read, so still won't have a clue who you are, you're going to have to work at it.