I do not consider any fantasy worldbuilding complete before you cannot tell me something about
- the culture’s sense of humour, with examples of popular jokes,
- popular literature VS classic literature,
- what children learn in school (especially history, maths, biology),
- the common grammar mistakes your conlang’s native speakers make,
- the culture’s cuisine, with recipes,
- toy production,
- the embarassing old songs people sing when they are really drunk, but would not admit knowing while sober.