Use a readable structure in the description
An effective description can follow this order:
- what you are selling;
- general condition;
- functionality;
- defects;
- modifications and repairs;
- included accessories;
- useful delivery information;
- any additional relevant notes.
You do not need to turn every section into a formal heading, but the information should be easy to locate.
Avoid one very long block of text with no structure.
The goal is to reduce the amount of work required for the buyer to understand the item.