Feynman Algorithm
c2.com
c2.com
0. Spent years dismantling every idea or concept and understanding it intimately.
This is almost always done out of sight to maintain the illusion. When people don't see the hard work, they assume you're a genius, not just working hard. I don't think there are any geniuses as such; just people with drive and enough experience and possibly good brain plasticity :)
I can get a stupid high result on an IQ test. That doesn't mean I'm a genius, just that I read up on how they work.
And then there's Messi.
For example, I've noticed that oftentimes when people get stuck solving a problem it's because they tried to move to step 2 or 3 without first completing step 1.
He didn't read the literature as he liked to be surprised. His sister told a story where she made him do so in one instance; preferred to figure things out himself. Was it inefficient? Certainly, but it added to his legend, satisfied his curiousity and often yielded a more-general solution.
Perhaps it was clarity of thought coupled with his (partially?) hidden self-training and toolkit. Perhaps it was a less-mechanical approach to physics, more intuition than perspiration? To me, Einstein falls into this category as well - the ability to ask pertinent questions and not worry about the answer and the number of apple carts being upset.
Certainly there was an ability to focus that was not common.
While sometimes the manual work to actually show that it works is quite small, other times it may take a month or even longer just to write down the derivation properly.
Ideas that come up after step 2, i.e. "think really hard", are ultimately just that: ideas. You need to ensure that you're not fooling yourself or that you have a case of confirmation bias (skipping steps in a proof because you think it's obvious while it actually isn't). Thus, I'd say step 3, "write down the solution", is at least as important as step 2.