Hi Anonymous,
In addition to the excellent advice and summary of Udayan I'd just like to highlight explicitly that also your cover letter needs to be structured very well. A rigid structure is not only a must in case interviews, it also begins with your application documents.
From a practical perspective it's efficient to map out the basic structure and specific topics you would like to highlight (e.g. with a mindmap or a simple bullet point list if you prefer), before really starting to write your cover letter.
Already seen to often that candidates just start writing upfront without ever having clearly thought about the structure and key topics they would like to communicate. The outcome of that approach is clear and you can immediately spot it as recruiter. On top of that it's always a mental challenge to discard something you wrote before - so better start with the correct approach in the beginning (doesn't mean you don't need to rework, but you don't need to throw away your previous version completely).
Hope that helps - if so, please be so kind to give it a thumbs-up with the green upvote button below!
Robert