Use fewer words. Publishers hate lots of unnecessary words because they add to the cost of publishing a book. Readers hate them because they just want to see who wins the pie eating contest (Joe!). Using fewer words will allow you to use better words in less space, and pull your readers along.
Here's an example. "Dave was very tired, so he brushed his teeth, used the can, took a shower, and curled up in bed with his dog, and a bottle of whiskey."
I'd rewrite that this way: "Exhausted, Dave took a shower and hit the sack with his beagle, and a bottle of Jack."
These are better, more descriptive words. It's easy to get into trouble describing everything and every action a character takes - show me, don't tell me, right? But remember, show readers what they want to see, not what they don't. See Writing Tip #3 for more on this.