The best way to learn how to write C++ idiomatic code is ... to write C++ code and to have your code reviewed by some advanced C++ developer.
You should also read some of the most famous C++ books (Effective C++ by Scott Meyers is a good start, Modern C++ Design is a bad book to learn how to write nice C++ code but is a great book if you want to discover and understand the concept of generic programming).
On top of all that, you should read much doc about STL and boost and learn a lot about iterators. Iterators are the key to use STL (and boost implementation of containers and algorithms) and if you don't know how to use them, you won't write C++ idiomatic code. Ever.
