The following are the best practices that are followed to write a clear and well-documented use case:
1) Capture both functional and non-functional requirements in a use case.
2) Include use case diagrams along with the use case.
3) Include the UI details/notes in the use case.
A business analyst must possess fundamental skills such as elicitation skills, problem-solving skills, communication, and management skills. Alongside this, he must have knowledge of IT skills, Software development understanding, and domain knowledge regarding the domain he is working in.