Garry Kasparov on Greatness in Chess

Kasparov in typical pose

"Enormous self-belief, intuition, the ability to take a risk at a critical moment and go in for a very dangerous play with counter-chances for the opponent - it is precisely these qualities that distinguish great players"

The five (!) world championship matches between Kasparov and Karpov produced produced some of the best games ever played

Kasparov definitely hit the nail on its head with the quote above. Especially the part about risk taking definitely applies to amateur players, too. One of the biggest obstacles for improvement is a player's natural tendency to avoid risk, and too greedily hold on to his pieces