I have often found questions which honestly do prompt the response "What have you tried?"
I tried posting a link to whathaveyoutried.com, only to find that it had been blocked. At this point, I looked through Meta, and found this post, which explained why it has been blocked. I agree with this decision as a general rule.
However, I'm still not totally clear on how best to handle these types of questions. Certain ones are very borderline. This question, for instance, has a lot of room for improvement, as the user is clearly asking for something specific, but hasn't bothered to communicate it.
Is it appropriate to flag these questions? If so, which flag do I use? If not, should I simply downvote, comment, and leave it be?
Note: In this case, I did flag this question, and it was closed - though in retrospect I would have liked to ask the user what they tried.