Tell the main story in as few sentences as possible. Follow up with more detail in appendixes. Tailor the language to the audience. If you're writing for fellow bioengineers, use the specialized words common to that trade. But customers trying to use the machine those bioengineers developed may not understand that language.
Clear writing comes from clear thinking.
If you don't fully understand the process or the problem, you can't explain it to others. Which means you must first establish your message. Clearly place it up front in the document. You don't write the same way to top management, your peers or the public. Tailor your approach to each.