If you’ve never read it, go out and pick up a copy of Strunk & White’s Elements of Style. It’ll cost you all of $5 on Amazon (after shipping, likely), and at just about 100 pages it will take you an afternoon to read. It’s a book that should be read by any writer about once a month, because it is so valuable for refining your writing.
One of the sections of the manual focuses on writing concisely. The phrase “Eschew needless words!” comes up a number of times throughout the manual. It is the tendency of probably any amateur writer to write more words than are necessary to convey the central point that is attempting to be conveyed by the author in question. Strunk & White say, “Eschew needless words!” Write concisely for effect!
So, here’s the activity: Take a page from a story or novel you’re working on. Make a copy of it, because I’d hate for you to ruin a page you’ve well crafted. Or just take a poorly crafted page that you don’t care about, whatever.
Take your page and go through and strike out every word that isn’t necessary to convey what you are trying to convey. If the meaning of the sentence can be kept without a word, take it out. Then count up the number of words you’ve removed. Then read what’s left and see how it sounds. If you feel it’s necessary, add back in some of the words you struck, one at a time. Stop when you’re satisfied.