From Self-Development and the Way to Power, by L. W. Rogers (13)

Now, there are three things that a person must possess to be
successful in self-development. If he has not these three
qualifications he will make but little progress; but, fortunately, any
lacking quality can be evolved and if one does not possess these three
necessities his first work is to create them. These three things are
an ardent desire, an iron will and an alert intelligence. Why are
these three qualifications essential to success and what purpose do
they serve?

More on foundations of personal development:

DESIRE...

IRON WILL...

ALERT INTELLIGENCE...