One thing to keep in mind is that keeping your costs down should never stop you from things that will increase your revenue.  I recently quoted a restaurant that had never put in hard alcohol because he thought his rates would skyrocket.  This being said, the key things are making sure you are with a carrier that likes your type of business and avoiding loss events as best you can.  

Most carriers will write a coffee shop, but some will be significantly better priced than others due to a desire for this type of business.  This also varies by location so what works in Florida may not be as good in Georgia.  Here in Florida I usually use Hartford for businesses like yours just to give you an idea.

What you need to be careful about is not expanding your business without making sure your policy covers what you are doing.  A coffee shop may be covered but your policy may become useless if you have any live entertainment like a poetry reading that is excluded.  Be sure to let your agent know everything you do at your site so he can quote the correct coverages.  Also, make sure you have updated revenue numbers when a policy renews.  You may not like your business interruption coverage if the claims adjuster is looking at a low ball revenue number from when you first opened.