Can any one suggest what is the best way to write good code that is understandable without a single line of comments?
I believe it's possible, if you consider the fact that not everybody likes the same style. So in order to minimize comments, knowing your "readers" is the most important thing.
In "information systems" kind-of software, try using declarative sentence, try to approximate the code line to a line in english, and avoid "mathematical programming" (with the i,j and k for index, and the one-liners-to-do-a-lot) at all costs.