I use the AutoReviewComments userscript with the following comments:
[Q] Too broad
Please only ask one question per post - only ask several if they are so closely related that it wouldn't make sense to split them up since they cannot reasonably be answered separately. That way, answerers that might be able to answer one question but not the others still can provide useful, complete answers to a question.
Please note that homework-like questions and check-my-work questions are generally considered off-topic here. We intend our questions to be potentially useful to a broader set of users than just the one asking, and prefer conceptual questions over those just asking for a specific computation.
[Q] Too little information
It's currently unclear what exactly this question is asking. Please add further information about the context so that potential answerers will know exactly what the issue here is.
[Q] Relevant question information in link
It's currently unclear what exactly this question is asking without clicking on the link you provided. To make questions more accessible and guard against link rot, please include all relevant information, such as the explanation of notation or specific terminology used, in your question.
[A] Link-only answer
Please do not post links without at least a basic summary of what they contain and how that content answers the question, since link-only answers become useless if the link rots away. Link-only answers are not considered answers here and will be deleted.
[A] Homework answer
I'm deleting this in accordance with our homework policy. Please do not give complete or near-complete answers to homework-like questions.
MathJax, not pictures
Please do not post formulae as screenshots, but use MathJax instead.
Text, not pictures
Please do not post images of texts you want to quote, but type it out instead so it can be indexed by search engines. For formulae, use MathJax instead.
[Q] Good question titles
Please consider writing more useful question titles, see How do we write good question titles?