Well depending on your business there are several risks. Lets say you were going to fix computers. What would be the worst case scenario?
1. Accidentally delete a customers data and you dont have a way to recover it?
2. Accidentally break the computer in the process of trying to fix it causing a higher labor cost?
3. Your store gets robbed and they steal all of the parts in your store and your customers computers.
You need to think of the worst case scenarios and see if you have a way to deal with them. Usually there is an insurance that will cover most things.
There's a massive list to this stuff in every textbook.
Motivation: Are you a driven person?
Barriers to Entry: (Market dominated by a few massiva players or diluted with a variety of competition)
Patents and Intellectual Property: Ensure your product can't be replicated and force you in to pricing warfare
Funding: Can you raise enough capital to finance the beginning of the business? Angel Investors
Lack of funding is the biggest risk. You need more money than you plan for, and you need to be self-sufficient without taking any money out of your business for 2 years minimum.
What are the risks and how do you overcome them?