The most common mistakes made by entrepreneurs when they start a business are lack of focus, not understanding the market, and not having a clear goal. The most common mistakes made by entrepreneurs when they start a business are lack of focus, not understanding the market, and not having a clear goal. Lack of focus: This is one of the biggest mistakes that many entrepreneurs make. They often try to do too many things at once or get distracted by other opportunities that come up for them. They also tend to spend too much time on one project rather than focusing on one thing at a time. Not understanding the market: Many entrepreneurs fail to understand their target audience and what they want out of their products. This leads them to make products that may be niche-specific or have features that aren't really needed by customers. Not having a clear goal: The main goal for many people starting their own businesses is just making money and getting rich quickly without really knowing what they are doing, there are many ways to achieve this and many different paths in which they can take.