What related experience did you have in the business that you want to put up? I am asking this because related experience in the field that you want to penetrate will save you from a lot of headaches when you start a business.
For one, you will know what your future customers are looking for and where to find them. Also, you will be familiar on how to communicate with suppliers, check inventory, returns and unsold merchandise. Another is that you will know how to improve your product and or service since you already know a lot about how it works and have an idea on how your customers might react as soon as you launch it.
Now, if you believe that you are not so experienced in the business your are about to begin, then take time to study the ins and outs of your business. Over time, you will gain the confidence that you need to start a business with clear knowledge and expectations.