Viswanathan Anand — Indian Celebrity born on December 11, 1969,

Viswanathan "Vishy" Anand is an Indian chess Grandmaster and former World Chess Champion... (wikipedia)

Chess as a sport requires a lot of mental stamina, and this is what that makes it different from a physical sport. Chess players have a unique ability of taking in a lot of information and remembering relevant bits. So, memory and mental stamina are the key attributes.
I attend to my fitness. I go the gym every day and try to maintain my physical fitness; without that, it is tough to take challenges on the chess board.
If you have a strong opponent, a competition is stimulating. I am generally most open to ideas when I have had a bad result. In chess, too, players specialise. This specialty then becomes an entry barrier.
It's important, according to me, to train in small doses so as to not lose the joy of playing chess. I personally think too many coaching and training classes may take away a child's interest in the game itself. The essential thing to do is practise often and, in case of a doubt, to consult a trainer.
If revenge motivates you, go for it! But the main thing is to set your game in order.