Error handling, adding comments, parallel test execution, creating data-driven tests & executing them through the CMD line.

know and understand basic rules of creating good API, how http works, how to create JSON/XML file etc..

ability to find out how logic should resolve by API from existing documentation and talk with developers,

ability to design tests that are relevant for API,

know how to use tools that are good for particular test tasks ( Postman etc.),

ability to analyze results of tests and how to update existing test suites after API changes.