If business plans are rejected after first scrutiny, it is usually because they fail to reassure the reader that the marketing and sales strategies will deliver the promised outcomes.
The second most-frequent problem is a lack of operational detail in terms of implementing the plan.
Both of these weaknesses derive from not having a clear understanding of your own strategy, lack of confidence or engagement with the strategy or a failure to communicate the strategy effectively.
A great deal of the potential for success lies in being able to get key people to engage with it and support it.
Getting the support has as much to do with (justified) optimism and enthusiasm as it has to do with dry statistics and over-planned detail.