hi, try these two links for info about running sweet shops, one is a business plan for a sweet shop, it costs £30 but might be worth it http://www.interstellar-solutions.co.uk/Sweet_Shop_Business_Plan.html
http://www.sweetshopbusiness.co.uk/
also have you thought about doing a short course in business planning? that way you could cover all the basics before you jump in at the deep end and you'd have the support of a tutor.
if you are serious about starting your own business make sure you do lots of research. these links should help you with general business stuff:
http://www.startups.co.uk/Start_up_guides.cy4fI_NoS63Ijg.html
http://www.businesslink.gov.uk/bdotg/action/home?domain=www.businesslink.gov.uk&target=http://www.businesslink.gov.uk/
http://www.newbiztips.net/default.aspx
http://www.clearlybusiness.com/advice-and-support/
http://www.rebecca-swift.co.uk/courses.aspx
http://www.starttalkingideas.org/next_steps/getting_started
good luck with your venture x