Pius Library owns many books on the subject of writing successful business plans. Use the Library Catalog to perform a keyword search for "business plans."
If you prefer to simply browse the shelves, many (though not all) of the circulating books on business plans are located on the 2nd floor of Pius, with call numbers beginning HD30.28.
One way to assess a particular company's financial health is to compare its financial statement and ratios to an aggregate norm for the industry in which it operates.