After reviewing this thread, one thing really stands out to me, and that is finding a niche like Brian mentioned and taking advantage of it. I live on the Oregon Coast and Brian really has started a pizza revolution in Oregon. Unless you go to Apizza Scholls or Ken's, you can not find artisanal pizza with great taste and high quality ingredients anywhere else in Oregon.
If you are going with a retail model, then location is going to be key. And do not forget to become an expert about leasing property, landlords can be tricky devils!
If you can, open your business where there is little to no competition like Brian did at Apizza Scholls. Also, start small and build up when you can develop a sustainable client base. I have opened two businesses, one that failed and one that is less than a year old. From these experiences, I recommend spending as much time upfront to plan your business in all details (ie. legal and business formation, accounting, marketing set-up, human resources and also your food operations). You can invest tremendous hours getting your business planned and organized right. Once you open, you want to devote all of your time to satisfying your customers and running the operational details of your business. You will not have the time to go back and recreate the things that should have been done originally.
When you are planning the business, this is a very exciting task and can be thrilling at times. The catch I have seen watching other new business owners is that they were so excited to open their business, that they ignored putting all the business functions together within a solid foundation. When they opened, things did not go according to their dreams and were rudely awakened at how hard it is to make a business successful. It will probably take three to five years to really know if you are going to make it. Plan to have your fun now, when you are self-employed, you will not have a life except the joys of your business.
Finally, if you can find a mentor to review your business plan, that will be a huge plus. You need someone with an impartial viewpoint to really study your plan and provide honest feedback. Also, before you start your business, set a limit on your finances on how much you are willing to invest and when you will cut the cord if the business is not making it. Do it before you start and remember that any failures you may have will also lead you to greater successes.