You could learn from the school of hard knocks or you could learn from this guy.As Electricmanscott stated, "flying by the seat of your pants", is exactly what I did. Know matter how many license or exams you can pass, school of hard knocks is the only degree that matters. I consider myself myself a competent electrician, but a mediocre electrical CONTRACTOR. So much about the business side of the trade I completely had to learn the hard way. Good Luck!
A link to his book.