I have asked myself the same question and have gone through business references and online. The answer is most probably need to start from you.
You will need to have what you want to do in mind, it can be either due to your interest or you have very good expertise in it.
So you know what you wanna do, what's next?
All of these processes should be written down on paper. And can be referred to as your Business Plan.
The following list should be in your homework/research!!!
1) What is your liking/expertise?
2) What is your mindset with regards to your business?
2) Who are your targeted customers?
3) Where to find your targeted customers?
4) What is your Unique Selling Point (USP)?
5) What is your business structure like? Business Process flow.
6) What are the cost involved? Fixed and variable.
7) What are your marketing strategies?
8) What are your goals, vision and mission?
You would need to know whether you be going online or owning a physical store or both.
The cost would make a whole lot of diffrences.
I would say that the right mindset and a good planning can lower your risk and bring you nearer to your goals. Don't forget action speaks lower than work. Be prepared for lots of work!!!!