Use fewer words.
In non-fiction communication–whether written or spoken–terseness is a virtue. Use as few words as necessary to communicate your point clearly, and no more.
This dictum is less applicable to fiction and conversation, but even here few will complain if you use fewer words.
At first it seems like we would naturally use fewer words. After all, writing more words seems like more work. But in reality, concise writing is more difficult. Why?
First, people do not think concisely. The first draft of most writing is full of clichés and lengthy sentence constructions that are the result of how we think. The remedy is revision: Go back and eliminate every unnecessary word. This applies to speeches as well as to writing: You should be practicing your speeches enough to know where to cut out extra words. (Also: Stick to your outline!)
Second, people learn bad habits in school. Instead of teaching how to write concisely, teachers demand that students reach a minimum quota for their papers. Naturally, the student wants to do as little of the tedious research work as possible, so he pads his paper with empty, meaningless words and phrases.
They teach that you should write by creating an outline–which contains most of the paper’s content–and then pad that to fill in the minimum space.
The remedy for this is for teachers to grade on content. Too often teachers grade primarily on grammar and meeting length requirements, because content is harder to grade than these objective factors.
Take the time to learn how English works. (I recommend The Writer’s Options: Lessons in Style and Arrangement by Max Morenberg and Jeff Sommers if you need someplace to start.) Revise everything you write at least once.
By writing more concisely, you improve your chances of getting your point to across to your audience.