As the title says, Feynman was no ordinary genius. His endless curiosity, questions and imagination enabled him to never stop. He also confessed he has never frozen because he didn't know something, on the contrary, that motivated him.
With all his humbleness and tremendous willpower, he was able to think independently, using the art of storytelling, simple examples and qualitative/conceptual thinking in order to explain complex problems. Also, geometric visualization skills helped him a lot.
Pieces of advice are "use your brain"and "read everything you can". Quoting Li Lu's interview in the last Graham & Doddsville newsletter, "know what know, know what you don't know, know what you don't have to know and there are always unknow unkowns."
Don't miss the opportunity to check out this documentary on Feynman's life.