You will need a solid business plan to present to any investors and the best place to start would be with determining your basic cost of operations. This will outline and help you determine how much money is needed to produce the product or offer the service you intend to offer or produce. It includes production costs, shipping, taxes, worker's wages, rent for workspace, etc. Knowing your cost of operations will be vital to determining if your business will be profitable, since you will need to make more than this baseline in order to remain in business. Be realistic. How many people will realistically use your business? How much will they pay to use your services? If either number is too small in comparison to how much it will cost you to stay in business, then you should reconsider or change your plans. You will need to plan ahead for all of the problems which can get in the way of running a business. Evaluate your competition; if their market share or product offering is too strong and stable, then you will have a very hard time breaking into the market. No one will want to buy an equally priced or more expensive version of a perfectly good product or service which already exists. You will also need to explore the associated regulations and laws, especially regarding taxes. You should ask your local state authorities, as well getting information from the IRS. Make sure there are no prohibitive costs, such as equipment which is too expensive to make the business profitable. For example, cars didn't take off until Ford figured out how to make them cheap by building more efficient equipment.

Summary:
Determine your cost of operation. Determine your potential market. Determine impediments.