Do not be tempted to write a 100-page business plan in the hope that its size will impress potential funders. Your business plan should be short, clear and well organised - perhaps 10-15 pages plus Appendix.
This matters because there is always heavy demand for investment, and few investors will be easily persuaded to gamble on an invention in preference to something that is more familiar and thus safer. Making your business plan easy for them to read and understand could be as important as your presentation of your invention.
A shorter business plan is also simpler to update, and easier for your team to use as an operations manual.
You should always be positive about your idea, but do not make claims about its prospects for which there is no evidence. Nor should you deliberately conceal known weaknesses. Experienced investors will not be fooled.You risk losing all credibility if your business plan attempts to mislead people, so let the facts do the persuading. As long as the potential of your invention is clearly demonstrated, you may even gain credibility if you can correctly identify weaknesses before someone else identifies them for you.