Short sentences and short paragraphs are easier to read and understand. Readability makes for a successful newspaper and also makes for a successfully funded grant proposal. Expressing yourself in simple words will take practice. For example, instead of currently, try now; instead of initiate, start; instead of expedite, move along; and instead of utilize, use. Using short words and short sentences keep your writing crisp and compact. The Wall Street Journal keeps the first paragraphs of their lead stories to less than four sentences long. Many paragraphs contain only a single sentence. Keeping it short will help you get your point across.
Using the active voice over the passive voice makes for a stronger proposal. Active verbs add energy and the active voice reveals who is speaking and taking action. The passive voice hides who is speaking and comes off as the voice of an institution speaking. Grant writing that is passive in voice just mumbles along and rarely stands out.
Avoid vague words and phrasings; instead go for accurate and exact. That doesn't mean that you cut all adjectives and adverbs, it means that you sharpen them to make your point. There are lazy ones and vigorous ones and some that are very overused and have become clichés. Would you agree that that is basically accurate and vitally important?
Now that brings us to down-to-earth and mumble-jumble buzzwords. Avoid educational jargon and the latest buzzwords. Use a down-to-earth word that says the same thing as the latest fad word. For example, let's stop reengineering things that have nothing to do with engineers. As I edited this article I certainly did not reengineer it, I simply edited and clarified. I will leave reengineering to the professionals. It's easy to change buzzwords to down-to-earth English. For example, instead of interfacing with your colleagues, perhaps you will meet and discuss? Instead of pushing the envelope you will try testing the limits. Clear and direct language always wins out over long-winded and heavy-handed.
The fatal flaw of unfunded grant proposals is the use of generalities. If you have thought through your proposal and have a strong project, be specific. You may have something very specific in mind but you fail to actually write it. Don't leave the grant reader guessing at what you mean. The specifics will speak for themselves. Take time to synthesize what you want to say and express it confidently in declarative sentences. Write simply and naturally.