Search google for: donut shop business plan, coffee shop business plan, catering business plan.
check out this link: http://www.ineedcoffee.com/07/coffeebusiness/
Also look at traffic counts to get a good feel for location.
Product market fit is tricky in food. MY family has been in pizza for years. My dad's won the columbus pizza bake off for both people's choice and judges in the same year. My brothers store has won the small competition for the same recipe. We have a great pizza recipe. I opened a store and in our first full year of business I did over 450k(Jan-Dec) opened in Sept. Still couldn't make a profit. Little caesers opened up and my sales went down about 15-20% for 2 years. And my brother's shop was the same way. Why because of their recipe no because it only takes a few people(that forgot how crappy their pizza is) that usually order to stop on the way for the kids because it's "hot n ready." Product market fit is a tricky bitch.