There are a number of reasons for this common discrepancy but we will focus on things that you can do to ensure you nail your presentation.
Nail your numbers
A universal criticism of most business plan presentations is the lack of consistency with the financial portion of the presentation. If you are not the detailed type and do not like numbers, make sure you assign this task to someone who does. Most investors are very good with numbers, especially when the numbers happen to be referring to the money they are thinking of investing. Do your best to make sure that every calculation is spot on and every projection can be tied to a financial figure that is coherent with the business plan financials. It can be a minute detail, but it is the little things that count.
Limit number of presenters
I recommend keeping the number of presenters to two is possible. Three presenters can be okay in extreme cases, especially if the business plan is about a product that is very technical. Most business plans are made up of two or three people with different specializations: an inventor, a financial person, and a marketing person. These three areas usually make up the majority of the business plan so as long as there is need for three presenters it should work out fine. You want to limit the number simply because it is easier to listen to one or two voices versus three or four. A lot of the content will be lost due to the personality differences that the audience will have to continually adjust to during the entire presentation.
This is usually a challenge for almost every person who is giving a presentation. Being natural, open, and transparent is the fastest way to create and establish a connection with an audience. No matter how tough the crowd is, if you can learn to be yourself and relax in front of them they will respond in kind. Outside of being simply being yourself transparency also implies honesty. If there are parts of the business plan that you know are fuzzy make sure to mention that before someone calls you out on it. If your financials are a little skewed make sure you explain why. If you have any fears that the projections may not be as realistic as you would like, mention that to the audience. Your honesty about the quality of your projections and your numbers will give the investors more confidence in you as a person. In reality that is who you are really selling.