If you lack understanding of the basic financials of the business, you will be dependent on a partner or employee who has it. At best, this can limit the profits that you can see because of the need to compensate this person for bringing this skill to the table. At worst, it can lead to financial decisions which are not in your personal best interest.
If you feel you are in this category, find the time to take some beginning accounting classes, including financial and cost accounting. Local organizations and continuing education programs at colleges may offer these. Learn how to at least read financial statements and how the basic cost and revenue drivers of the coffee shop business can mean the difference between profit and loss. Know what you have to offer investors so that, even if it is your financial wiz partner presenting the deal, you know what you are getting into.