First use case
Once the first success is achieved, the developer likely wants to chain several API requests in order to achieve a business outcome. In many cases, the developer is not a domain expert and has only gotten vague input from product owner on what the goal is.
Provide business context
The API portal description should provide business context. For example, describe the difference between a corrective-work-order and preventive-work-order resource.
This may be challenging for the API producer DevOps team to create, so ensure the product owner dimension is involved.
Low bar for reaching out
Provide a slack channel for your API, where developers can ask informal questions for example how they best can achieve their wanted business outcomes. Do not force them to register a support ticket or similar as developers will postpone this untill they have exhausted all other options.
Have the slack channel become the home of a community of API consumers and the API producer DevOps team. More often than not, you will see API consumers helping each other out.
Provide tools for grouping API request
Encourage the use of tools like postman, where developers can setup a collection of API request they need to achieve their wanted business outcome.
The API producer DevOps team should be responsible for maintaining a reference postman collection of typically API request grouped in a natural manner (as a golden rule, one request pr example of an endpoint in the OpenAPI contract).