I think the three reasons entrepreneurs so often give the advise to just "go do it" is that a) the biggest barrier they faced to their own success was the psychological barrier to actually committing to taking the plunge and b) the key to their success was in taking an unconventional approach to at least some aspect of their business and c) they no doubt set off in a bunch wrong directions that had to be corrected, and the only way to learn that was to make those mistakes.
The catch is that while by nature we are risk-averse, there is a degree of reflection that would definitely improve your chances of success. While big wins tend to require unconventional approaches, you can't just break rules at random: you need to understand the rules and the reasons behind them better than everyone else. Finally, mistakes are a key part of entrepreneurship, but learning from them is essential, and that second part is harder than successful entrepreneurs appreciate (because to be successful, you've had to put together a pretty impressive track record of learning from mistakes). Experience is key to interpreting events to learn the right lesson.
The catch is that while by nature we are risk-averse, there is a degree of reflection that would definitely improve your chances of success. While big wins tend to require unconventional approaches, you can't just break rules at random: you need to understand the rules and the reasons behind them better than everyone else. Finally, mistakes are a key part of entrepreneurship, but learning from them is essential, and that second part is harder than successful entrepreneurs appreciate (because to be successful, you've had to put together a pretty impressive track record of learning from mistakes). Experience is key to interpreting events to learn the right lesson.