Good question.
Your first step would be to do a SWOT analysis. SWOT stands for Strengths, Weaknesses, Opportunities, Threats.
Strengths: What are some of the strategic advantages of your business? Strengths could include an established customer base, production efficiency, cost-effectiveness, and others.
Weaknesses: What are some of the strategic disadvantages of your business? Many small businesses lack economies of scale. Also, your geographical scope could be limited.
Opportunities: Ways you can grow your business. Could include things like expanding into new markets or creating new designs.
“Threats:” Things that could hurt your business. Could include things like wars, recessions, natural disaster, and competitors.
Once you have a SWOT analysis done, you will have a better idea of (1) whether it is worth it for you to open the business in the first place, (2) whether there is anything you can do to take use your strengths to take advantage of opportunities, and (3) whether there is anything you can do to shore up your weaknesses or plan for threats.
For more information: http://en.wikipedia.org/wiki/SWOT_analysis
Hope this helps.