.NET RESTful client best practices [on hold]

I am setting up a Web Api project in .NET Core that will use 3 different airlines' APIs. I want to create an API that will merge resources from these APIs and will return them to my separate Angular app. I want to use 3 service classes, one for each individual airline. These classes will be called asynchronously from a controller and from a "WebJob" as well to download informations that are persistent like codes of cities for example. I struggle because I want to use as much of the best practices in terms of creating a REST client and controllers as possible, can you provide me some useful informations how to keep everything shiny and sparkling?