I already have my own business and from my own experience I can say that the main obstacles are absence of ideas for your company, lack of knowledge about business strategies/tools and absence of a start capital. The last one like it was mentioned in previous responses is even a more common thing than two previous ones.
But even if you have the one, anyway you should have a clear goal and understanding of what you're planning to do, also a good business plan and enough experience/knowledge in business strategies. It's simple, if you start a new company without knowing about general competition in your certain sphere, there's a great risk, that you'll fail soon.
But the start capital is the important thing too because you'll need money for providing your production/service, hiring the workers, opening an office, advertising and so on. Don't forget about business taxes and security systems for your company, like for example fire protection
https://www.americanbackflowprevention.com/, backflow prevention and so on because your workplace should be always safe and comfortable for you, your workers and clients.
You also should be patient and hardworking at least for first years, with good time-management skills too, and as I noticed from my experience not so many people are ready for this.
i m not worry with my competitors as if your market is niche, they wont be able to penetate easily