Question

1. What are the best practices and patterns to be followed for designing APIs?
2. How to achieve implementation hiding the best way (C++/Java)?
3. Designing APIs which are generic in nature?
4. Any reference books/links which guide with neat examples to beginners?

Answer 1

This might be useful for you.

The Little Manual of API Design (wayback machine)

The Little Manual of API Design (original; dead)