Lesson number two, lads.
Entropy.
Now, now. I know you were sleeping in physics class. It's okay, we're not going to mess with the 2nd law too much (if you don't get that reference... stay in school).
We are going to apply a physical law to writing. Mind boggling, yes. It's also awesome (in the non-degraded sense of the word. That's a pun that you'll understand later).
Entropy is the slow degeneration of something. As X is used, X becomes weaker. Cars need oiling lest they rust. Water goes stale. Your mom's bed needs new springs after dealing with her girth for so long. Things eventually wear out.
Now, when applied to writing, this means exactly two things.
"Don't use words too big for the subject. Don't say 'infinitely' when you mean 'very'; otherwise you'll have no word left when you want to talk about something really infinite."
--C.S. Lewis
What he said. C.S. Lewis was a better writer than you and I will ever be. So shut up and listen to him. (He was also a linguist, a Dean of Oxford, worked at Cambridge, helped pen The Lord of the Rings, and was BFFs with the likes of Tolkien.)
I doubt that many of you use "big boy" words all too often, so let's skip along to the next bit. Rapid use.
An interesting principle here is that if you use a word in too quick a succession, then that word will lose its power over the the reader. Interestingly enough, if the the word is a small, weak word, then the the reader won't notice its overuse. I repeated the the word "The" twice every time in this paragraph, interesting, eh? You may not have noticed. I am almost certain that you noticed the repetition of "Interesting," though.
When you use any word too often, you lead the reader to notice that they're reading (and that pulls them out of the story) and you might also hint to them that your vocabulary sucks. By avoiding the reuse of strong words in close succession, you basically remove some of the 'wear' that readers will receive, this makes for a smoother, softer flow.
Basically, don't use the same big word too often, or the ghost of C.S. Lewis will set a pack of rabid lions after you. And his lions tend to not die all that well.
Keep warm, stay cool,
Edgar A.