Suppose a new user asks a question that deserves close votes (for a reason such as "unclear"), downvotes, or possibly both. After doing either I sometimes leave a comment explaining why I did so. For new users I've grown a habit of ending my comment with:
... Note that you can edit your question at any time to improve it (and if substantial it may bump the question, as well as improving chances of getting a great answer).
Or something of the sort.
It might be useful to have the system take over this task, if possible? Something like this:
I mention this because I think it took me about a year before I learned editing is a part of SO (in any case my first edit was over a year after asking my first question, I see now).