Describe 10 practical methods with which developers can design APIs to enable intuitive, consistent, and efficient usage, thereby significantly improving the developer experience.

Context: [API design, developer experience, usability, REST, GraphQL, interfaces, programming, software development]

Goal: [clear and understandable API structures, easy integration, reduced learning curve, improved error handling, consistent documentation]

For each method explain:
1) a concrete design decision or practice that contributes to optimization
2) practical tips for implementation or testing of the API
3) the expected positive effect on the usage and acceptance of the API by developers

The methods should:
- be easy to understand and directly applicable
- be relevant for both backend and frontend developers
- address typical challenges in API design
- motivate designing APIs to be user-centered and maintainable