I honestly love being able to write other people's OCs because it lets me play with new relationship dynamics and new personalities, also nice to see new characters. I usually ask what their personality is, how they interreact with other OCs or their partner, also helps to have some visual reference or art of the character to know how to describe them and get a better idea of how they present themselves.
The only time I had a hard time writing that involves settings is when I have to write in a specific setting or some established world. Having to conform to that setting can be difficult to do because I feel like I have to be more conscious of it or mention it a bit more. Having more freedom with the setting and being able to let things just be without having to worry about what is happening in the background is really freeing~
