Begin by finding out every detail of the product or service. Treat it like a research project. Read trade magazines, articles, and stories on the business, industry, or occupation. Surf the internet for every bit of information you can find. Seek out people in the same business and ask for their opinions of your product or service. Don\’t be secretive. People in the same business will give you very good feedback on the viability of your idea. Ask your bank manager for his or her opinion or advice. Bank managers see hundreds of business ideas every year. They are extremely knowledgeable about what is likely to work in the marketplace. A five-minute conversation with my bank manager some years ago saved me $200,000 in buying a business. He pointed out two or three things that I had completely overlooked because of my inexperience. Ask your friends, family, and acquaintances for information, input, and ideas about your business idea. Cast a wide net. Especially, visit prospective customers and ask if they would buy that product or service from you. Ask if they could sell the product or service to others. The fact is if you had been hired as a consultant to evaluate this potential business, develop a suspicious attitude, and accept nothing on faith. Look for what I call the fatal flaw in the business idea. Then look at the business as though you would be in it for the next 20 years.