How much/what kind of technical details should be covered? what other
aspects of a project should be covered?
I'd look at this from a few angles:
First, make sure you give enough context on the project in terms of how many people worked on it, how long was the project, what kind of budget scope was there,e.g. was this a $10,000 project or a $10,000,000 project, and what technologies were involved to what scale.
Second, what roles did you fill on this project. Were you an analyst handling gathering the requirements? Did you design the solution? Did you help estimate the deadlines for the project? Did you write any code? Did you test code? Did you help with deploying the code?
Third, which practices were used. What methodology was used,e.g. Agile or Waterfall? Were there practices like Scrum, pair programming or any BDD, DDD or TDD done? This is the last part as once you have given the setting and roles done, this is what else was there to pass along.