If you have strated your entrepreneurial journey, it means that you have already conquered some of the challenges like finidng the right idea, fear of failure, lack of experience! These challenges will keep coming up once in a while and you will resolve them.
From my perspective, securing the capital is most important at this stage. And the "capital" doesn't mean funds, it also means "advisory", "complentary expertise", and ofcourse the right "investors". This definitely requires the founders to know what they are good at and what they are not, recah out to people who can complement their strengths and weaknesses, and trusting people with responsibilities.

Many entreprenuers start with an idea but eventually their business will be somewhat different! This means that adapting to the needs and wants of your end users is critical. Stubborn stickiness to the original idea with no sense on what the world needs is a big factor for failure. This can happen ONLY if there is a stable and trusted team with clean roles and responsibilities and transparent discussion! One of the mistakes that many founders do is that they think that as a founder, they should hold executive roles! While most of the time it works, there are times, founders should bring in the executives who can grow their business. At the end of the day, what matters is positive cash flow!

Thousands of startups come up everyday and many of them will be your competitors in one way or the other. The new startups will have newer and better ideas. An entrepreneur who has a running business will be consumed with operations, business challenges, client management, and so many aspects of running the business where as a new entrepreneur will focus mostly on innovation and solving the 'newer' end user challenges. So "sustained innovation" is the only way to stay competitive and ahead of the game. If we take successful companies as examples, we can learn how they contineoulsy innovated their products, services, and solutions to meet end user demands and sometimes - offer something better to the end user.