Now, there are many good resources out there to help you become a better writer (or editor, rather)—couple of my favorites are Self-Editing For Fiction Authors, and Eats, Shoots and Leaves—but after I read some blog posts that were needlessly long on this subject, I figured I'd give a condensed version (big fan of brevity here) as well as provide some things that drive me crazy that my writing buddies do that I know appears no where else in published fiction (because they're things you should not do).
All right, first thing is first, stop using adverbs. Quick review in case you've forgotten, adverbs are what they sound like, they're a word that modifies, or "adds something" to a verb. Like slowly, quickly, etc. Most of these end with -ly, but not all of them (some other big ones that don't end with -ly are just, began, and started). The reason we don't use these words is because they weaken the verb.
Example: Mark quickly pulled the trigger. Versus: Mark pulled the trigger.
There are exceptions to this rule, of course, but it's a rule for a reason. Nine out of ten times the sentence will be stronger without the adverb. Avoid these like the plague.
Don't describe exact distance or exact passage of time. Unless you're writing a story where the exact passage of time is integral to the story (maybe the MC only has so much time before the bomb blows up, or the serial killer is going to drop his wife off a bridge if he doesn't get there by a certain time, or whatever) you don't need to give it to me.
Examples of doing this: Mark stopped talking for five minutes before finally saying something.
Without the passage of time it would look like this: Mark stopped talking. He brushed back his hair, and stared off into the empty street.
So, instead of just telling me that time passed, you need to show it. See how I got rid of the telling of exact time, and replaced it with a beat? (a beat is an action a character does) That's what you need to do when you feel tempted to tell me time passed.
Another example: The heroes made camp, sleeping for eight hours before waking up and disassembling their tents and cookware.
Here it is reworked: The heroes slept. When they woke, their bodies on edge from a restless night, they...
So, really there was more than one problem with that example. One, it tells the exact passage of time, which is boring to read, and two, nothing happens in the sentence that I want to read about. So in the reworked sentence I made them tired, which tells us they didn't get much sleep without me just out right saying it, and from there the sentence trails off on what we assume will be some description on where their journey in the story is going to be next, rather than just some description of them mindlessly disassembling their camp (Who cares about that! Get to the story!).
Now, the rule of not telling exact time goes the same for distance. I don't need to know that Jim was standing five feet to Jennifer's left, or that the coffee pot sits twenty-five feet away in the kitchen. I can fill that in myself. Just give me the action, paint the scene, and I'll use my imagination for all the little details. Including exact distance only makes me feel that you (the writer) don't think I'm capable of inferring anything, which makes me want to stop reading.
Example: The soldier was fifteen feet from Marcus' blade. Marcus road toward the man.
Reworked: The soldier stepped back, staying out of Marcus' reach. Marcus road toward him.
In this version we've cut out the exact distance, but we've still shown the reader that the soldier is not close enough for Marcus to attack. This is better because it shows where the soldier is through an action, while also cutting the on-the-nose description of "fifteen feet."
Well, there you have it, a few things that you should avoid while writing fiction. This is by no means a complete list, but hopefully it will help point you in the right direction. As I stated at the beginning of this post, if you're serious about writing, you ought to head on over to Amazon or AbeBooks and pick yourself up a copy of Self-Editing For Fiction Writers and Eats, Shoots and Leaves.