In a novel, it's rarely the case that every single word counts. You don't have the economy of a short story or poem. And yet, if you establish a pattern in wasting a reader's time throughout your novel, you'll lose them as effectively as if you'd written something offensive. While that usually comes about with long scenes that don't address the plot, it can also happen on a sentence level. Here are a few ways how.
- Progression—A good sign you're delaying your sentences is if you talk about progressions on a task, rather than the task, itself. "Started to," "in the process of," "finished," "worked on," and similar phrases halt the action, rather than moving it forward.
- Synonyms and Definitions—This is one I know I'm guilty of. I write something like, "Conciseness, or using just a few words to describe something, is a skill that doesn't come naturally." It wasn't necessary that I define the term, but I did it, anyway. I'll also start to list words that mean the same thing, when one would do.
- Redundancy—"PIN" is an acronym for "personal identification number." Calling it a "PIN number" grates on my last nerve. "ATM" is "automatic teller machine," so if you call it an "ATM machine" within your text, I will question your intelligence. It's a great phrase to put in your character's mouth to show he's not all there, but, if you don't know any better, I have no sympathy for you. Similarly, empty words that add nothing to the sentence don't belong.
- Qualifiers—If you've heard adverbs are evil, this is why. "Just," "only," "really," "mostly," "usually," "basically," serves to weaken a sentence, rather than help it. Similarly, if you describe how dialogue is delivered (flippantly, sarcastically, seriously, quietly), your dialogue is failing.
- Fluffed-up Phrases—"The fact that," "The reality of it was," "The system of," "The mechanism that," "As we all know," indicate that the writer is going about this story the long way around. These phrases and similar have their uses, but overuse makes the story look like a NaNoWriMo gone awry.
It is possible to use any or all of the above without stalling your sentences in the middle. Filler words can contribute to the overall flow of a sentence, and they can be used in dialogue to show the character is a blowhard.
During your editing phase, note any of the above you find in your manuscript. Keep a file of them. If you notice they keep cropping up, start to pick and choose where they belong, and use ctrl+f (cmd f on a Mac) to find instances of filler.
Your writing is stronger when you don't fill it up with unnecessary words. Also, readers appreciate that you didn't make them wade through useless text to get to the good stuff.