Disclaimer #1: I've grown to dislike giving writing advice. Everyone's opinions differ and I don't believe there is one "right" way to do things.
Disclaimer #2: I am not an expert. I only just dove head-first into the writing business three years ago, and my book has yet to hit shelves.
Having said that, I do think that I’ve learned a lot in the last three years. And one of the things that I consistently notice when critiquing work for others is overwriting. I did it myself (and probably sometimes still do), before someone wisely pointed out that I was way explaining things that the reader would and could easily surmise on their own, which often times made the writing clunky. When I put an end to that bad habit, I noticed much cleaner, more professional writing.
Some examples, yes?
I reached up and brushed the hair out of my eyes.
If I’d simply said: I brushed the hair out of my eyes, the reader would know that I had to reach up to do so. I didn’t need to tell them that.
I bent over and picked up the book.
I challenge you to pick up a book without bending. Okay, smartass, so you crouched. Still, who cares whether you bent or crouched? The point is that the book was picked up.
I put the key in the ignition and twisted, starting the car.
We all know that in order to start a car, a twisting motion is necessary. Why not then just say: I put the key in the ignition and started the car. Or even simply: I started the car.
Here are a few common ones:
I nodded my head.
I shrugged my shoulders.
Can you nod a body part besides a head? Shrug anything but a shoulder? If I’d just said: I nodded, or I shrugged, the reader would instantly know which body parts were used.
This is just one aspect of overwriting, obviously. There’s also the issue of over-explaining (Just in case the reader didn’t get that, I’m going to explain the exact same thing in another way!), going overboard on the adverbs to really drill home a point (“He dashed hurriedly across the parking lot”—adverb, totally unnecessary as dashed mean to run quickly), using multiple adjectives where one more could be more powerful, etc. But the point is: trust your reader to draw some of their own conclusions. They’re pretty smart. You needn’t hold their hand!