Writing for News Limited, the 34-year-old New York Red Bulls star said he knocked back the opportunity to return to the English Premier League in a bid to keep his body in the best possible shape.
"Now almost eight months has passed (since the Socceroos qualified), and thoughts are turning to Brazil – first, earning myself a place on the plane, and then hoping to do ourselves proud when we get there," wrote Cahill.
"From a personal point of view, just to be in with a shout of going is vindication of the strategy I’ve followed to maximise the last years of my career. It’s about looking after your body, taking pride in your professionalism – and hopefully the rewards flow from that.
"To have the opportunity to score at a third World Cup would be just outstanding – I don’t think too many others could say that – but before that comes, ensuring you have the form and fitness to warrant selection in the first place.
"Hopefully it should mean that come June I’m at peak fitness for the World Cup. I’ve been fortunate enough to play with and against a number of Brazilians, who’ve told me some great things about their country."
Cahill also felt it was time for him to step up to a leadership role in the team.
"At the 2006 World Cup, one of the most captivating sights was the Brazilian fans dancing just as hard before we played them as after," he wrote.
"This time around I hope to be one of the senior guys, pointing out sights like that to the younger boys and reminding them to take it in, to enjoy the experience and take memories away. At Everton I was proud to be part of the core group helping younger players like Ross Barkley and Jack Rodwell as they came through as teenagers.
"The best advice I had, and will pass on, is to play each game like your last, and never to rest on your laurels. We’ve still got much to achieve."