Use clear, simple English and define all jargon terms . This is particularly true in a scientific field such as physics or chemistry or molecular biology. Sound knowledgeable, but use simple sentences and active voice to convey your meaning clearly. Look for special resources available from the agency to help you. Use illustrations where possible to reduce words.
People are time-starved today and the eye naturally gravitates to a picture.
Don't just describe the drawing. Put your key features or messages in the captions to the drawing or picture. Captions always get read. Use a cover letter to provide situation specific information. If you have confidential information in the proposal, note it in the letter.