People don't usually read reports for recreation. What that means to you as a writer is that you need to be economical with your words. If you're having trouble keeping a paragraph short, focus on the key ideas. Look for whole sentences that offer only tangential information or are only qualifying remarks to what you've already said. Put those in dependent clauses instead of as whole sentences and take out any redundancy.
Reports usually follow a certain format that your industry or research field has set in place. And there's usually a good reason for that. If you're not familiar already with the format, take time to look over the guidelines and try to understand why the format is the way it is. Use that form to your advantage both in presenting things clearly and in writing the report quickly. Keep the various sections in mind and resist the temptation to put in more detail than you need. Think about what you would be looking for in any section if you were reading this report. For example, details about how computers are changing the operation of cranes probably aren't as important as how much the crane can lift and how fast it can be assembled.
Make numbered paragraphs or those in bullets easy to read by putting technical details in parentheses. Bullet points are some of the most commonly read sections of reports, so only put clear and concise statements there. Technical information is usually the heart of a report, since your conclusions are based on it. Make it clear where that information is in your report and put as much of it there as you can. Don't use footnotes for technical information because that makes it hard to find.