After seeing a few off-topic questions today, I thought it might help to add placeholder text to the question texarea.
The question page currently looks like this:
"How To Ask" is easy to miss or gloss over, and has emphasis on the wrong part ("code from projects you are working on for peer review", instead of "relevant code sections must be included in your question").
I propose adding placeholder text to the main textarea, just as there is placeholder text in the title field. Something along the lines of
Your question must contain code. Please ensure that your code works as intended; we do not fix broken code.
I realise there will always be off-topic questions, but I think this is a relatively simple way to reduce the number of them.