Style and tone matter a great deal in proposal writing. The customer’s selection process is really a process of elimination. Your job is to make it as hard as possible for him to eliminate your proposal. One way you can do this is to keep your writing from boring him to death. That’s a sure way to make him lose interest.
When you’re writing your proposal sections, try to achieve a “clear” style. Most of us know clear writing when we see it, though it may be hard for us to define.

Clear writing is easy to read. The language is simple and familiar, the sentences short and to the point.

Clear writing is also efficient. The writing does not include extra words that clutter up the document.

And finally, clear writing is easy to understand. Concepts are explained in language appropriate to the context and the readers.

The best thing about clear writing is that it makes it easy on the reader; he can see what you’re getting at quickly and does not have to waste time trying to figure it out. This will make him happier. And that’s what you want.

Here are some tips:

• Write to express, not to impress. You’re not going to score any points by showing off your vocabulary. Don’t write ingress and egress when you could write in and out. Don’t say “It will greatly facilitate our work if we can augment our staff by three,” when you really mean “It will help us if we can add three people to our staff.” Writing like this puts people off.
• Avoid long sentences, which by the way are a hallmark of technical writing. 55 word sentences are the kiss of death; they are hard to get through. In fact, no one will get through them. Your average sentence length should be 17 words.
• Avoid jargon. Jargon may be clear to the people in your technical field, but you can’t be 100% sure that all the people reading your proposal will be in your technical field. Managers with no technical background at all often read proposals. When you write proposals you should minimize the jargon.
• Write in the active voice, not the passive voice. The passive voice kills the reader’s momentum. It is an unnatural way of expressing an idea; we do not think in the passive voice, and we usually don’t use it when we speak. We would rarely say, “A records database will be designed.” Instead, we would say, “We will design a records database.”
• And finally, proposal writing style is characterized by citing benefits to the customer throughout. Don’t simply say you will do X. Tell the customer that you will do X, which will result in benefit Y.