A good story is like a well-tuned car. When everything works well, you can just get in and enjoy the ride. When your headlights don't work, the muffler has fallen off, and your trunk is being held closed with a bungee cord, the problems are all you can think about.
Here are some tips to help your readers enjoy the ride rather than worying about the springs sticking out of the seats.
1. Mechanics
You’d never take your car on the road if the tires were full of holes. So don’t send out your manuscript without perfect mechanics: grammar, punctuation, and spelling.
I see a lot of writers who expect their crit buddies or beta readers to fix their mechanics, but those writers are cheating themselves. They’re never going to get an in-depth critique that will help them make their story better. Nobody worries about critiquing plot, characterization, or dialogue when they’re reading work by someone who misuses every other homonym.
If you’re not good at grammar, that’s okay. Take a class at your local community college or buy/borrow some reference books. Strunk &White's
The Elements of Style 
and
The Chicago Manual of Style 
are great resources to rely on until great grammar and punctuation becomes second nature to you.
2. Tightening
When a reader says you need to tighten your writing, she means you need to remove clunky, extraneous words and phrases. Often they're hard to see until you know what to look for, but they rattle around like loose screws. Here are some tips to help you find and get rid of them.
a. Use strong verbs rather than adjectives and adverbs.
Example: She flung the door open is better than S
he pushed the door open forcefully.
b. Remove redundancies.
Example: “What were you thinking, you idiot?” he said irritably tells us that the person is angry twice — once through dialogue and once through a verbal tag. Just stick with the dialogue and cut the verbal tag completely.
c. Say everything as efficiently as possible. Pretend that you’re being charged for every word you use. Don’t you want to make sure you’re getting your money’s worth?
Example: He walked right up to her, so close they were nearly touching, trying to intimidate her with his size becomes
He moved closer, using his size to intimidate her.
d.
Avoid cliches. We often use cliches because they so often fit. "Prim and proper" or "tall, dark, and handsome" may very well fit your characters. The problem is, they fit a lot of other people's, too, and since you want your story to stand out from the rest, you need to make your descriptions
unique.
Example: It was raining cats and dogs becomes
It was raining, huge warm droplets that pattered on the blacktop like thousands of tiny feet.
3. A Fresh Coat of Paint: Being Unique
When you go to buy a car, you want the most mechanically sound car you can find, but if you're like most people, you also care how it looks. You can really make your writing stand out if you can find unique ways to say things. Don't be afraid to indulge in a little wordplay, trying out unusual turns of phrase or comparisons.
a. Indulge in the sensory details. For each scene, you need to close your eyes and imagine how the situation smells, tastes, sounds, looks, and feels. You probably won't describe each sense in most scenes, but knowing will help you choose the most relevant and striking details.
Example: Like soft, dark wings, his voice folded around me. I was at once enveloped by warmth and aware of coldness at the base of my neck. Legs stretched out in front of him, feet braced apart, he was watching me.
b. Use metaphors and similes. Don't be afraid to compare something to something else, directly or indirectly, as long as you do it in your own words.
Example: A traffic light flashed by; the wire that had once held it aloft eddied across the road in a black tangle. Green and red and gold chips were spattered across the asphalt like misplaced casino currency.
Want to learn more? A few books that have really helped me get better at editing my work include
*
Write Tight
*
Revision and Self-Editing
*
Self-Editing for Fiction Writers: How to Edit Yourself Into Print
*
Make Your Words Work: Proven Techniques for Effective Writing
Carolyn Kaufman, PsyD writes fantasy, scifi, and nonfiction. She loves helping writers "get their psych right" in their stories, and her book on the same topic, THE WRITER'S GUIDE TO PSYCHOLOGY: How to Write Accurately About Psychological Disorders, Clinical Treatment, and Human Behavior is now available for pre-order. Learn more about the book at the WGTP website or ask your own psychology and fiction question here.
Jane Lebak is the author of The Guardian (Thomas Nelson, 1994), Seven Archangels: Annihilation (Double-Edged Publishing, 2008) andThe Boys Upstairs (this December from MuseItUp). At Seven Angels, Four Kids, One Family, she blogs about what happens when a distracted daydreamer and a gamer geek attempt to raise four children. She is represented by Roseanne Wells of the Marianne Strong Literary Agency.
