Back to the OP... here is a free online resource by the Mensa Foundation which discusses internal motivation: Lit From Within. Slide 41 of 43 in the Prezi reminds us that self-concept should be realistic and skill-based. Slide 42 reminds us of the role of effort (actually, grit): destitutus ventis, remos adhibe (deprived of the winds, take their oars).

Dweck (author of mindset) is one of several sources listed in the presentation.