In other SE sites, they have a system where if you downvote a question or answer, you also provide a comment stating why you're downvoting it.
This gives askers and answerers the opportunity to realise their mistake/improve upon their questions and answers.
I notice this isn't in play on https://chinese.stackexchange.com/ and I think it should be. It's a good system.
EDIT: P.S.: similarly, commenting with reasons for upvoting are also appreciated and helps askers/answerers know they're on the right track, and why.