How to Invest Into Yourself

Ask yourself, are there skills that i can enhance? Is there a way that i can increase my competence? Can i take a class on ales, if i'm in sales? Can i hire a coach to coach me? If i'm an executive? Can i go and become an apprentice to such and such a company to make more money? What can i do to increase my earning ability? Because the best investment is almost always in yourself.