Bobby Fischer. What methods did he use to learn chess?

He lost more games than any of us. Until he became really, really good.

See the documentary "Bobby Fischer against the world". It's on youtube. Some of the people close to him I.E. Larry Evans, Anthony Saidy etc. comment on this and when and how he made the quantum leap. First he was their peer, then all of the sudden he was just better than everyone else. Keep in mind that he had no father and was basically raised by a group of GM's. Basically there is no mystery to it, he just worked harder than anyone else. He put in the 10,000 games needed to learn. His story is a tragedy just like Morphy. All Bobby ever had was chess, when he didn't have that all he had was madness. Thank god he was able to estabkish Chess 960 as we know it today before his demise. So he contributed that and an example of potential unaided performance. I consider him the greatest player of the precomputer era. I don't know that he would be that successful in todays environment. Had he played Karpov, I think he would have won. However, I think that Kasparov and the next generation would have wiped the board with him. So the answer you are looking for is that Bobby let chess consume him, it was his escape from the world. If you want to study like that, go ahead. In the end you will meet the same demise. Play it for the enjoyment. That is my recommendation.

I think Bobby Fisher was just a great chess talent and he started young.

But also he worked very hard at it.
He got his biggest boosts in playing strength during periods when he did not play, only analyse.