Under this umbrella of entrepreneurship is "the mission".
Which requires specific skills, knowledge, processes, tools and team.
These are the focus areas for learning.
If a service business, the entrepreneur will lean to learning skills related to hiring, leading, people development, accountability, etc.
If a software widget, the entrepreneur will lean a different direction for learning.
Learning how to be an entrepreneur - is about taking "nothing", saying "I am responsible" and creating something of value that others will rave about (and pay for).
I took night courses at college to learn the lay of the land about business structures, risks, rewards and SWOT.
I found and relied on mentors to help me avoid unnecessary bumps. (Though I did not ask them to be a mentor, I just stuck close... listened and followed their pattern.)
Templates already exist. It is a matter of being aware, recognizing them and then puzzling out how to use this for that. Henry Ford did not invent the assembly line. He saw it in action and applied the processes.
Wishing and trying to learn something that is beyond our reach - not wise.
Staying motivated happens by sticking close to those who are inspirational thought leaders. (Which can be a 4 year old grand daughter to an 80 year old engineer)
One solution is to hire and/or find a partner but that too requires new skills and wisdom. :)
There is not truly a "preparation" for entrepreneurship in and of itself. Each scenario prepares us for the next, and the next... It is not a failure as much as another step.
To learn the path by going to class is only a hint of what is to come when we walk the path.