1. Define API requirements and target audience.
2. Choose between REST and GraphQL based on use case.
3. Design resource endpoints and schema (REST) or schema definitions (GraphQL).
4. Implement API versioning strategy (URL, header, or query parameter).
5. Implement pagination and filtering for resource collections.
6. Implement consistent error handling and status codes.
7. Consider HATEOAS for REST APIs.
8. Implement resolvers and DataLoader for GraphQL APIs.