It's always a good idea to look at highly up voted questions. Two tags come to mind here:
summary-request:
Questions explaining concepts (e.g. sovereignty), organisations (e.g. the EU) or events (e.g. Brexit) in simple terms without assuming much prior knowledge of the subject
These summary requests are meant as introductions to a subject. It's hard to summarize these questions because it's a bit of a meta tag. When you scroll through the list though, you will probably come across a few subjects you haven't heard about before: a specific report, a bill passing through the legislature, but also more common subjects like Brexit.
And political-theory:
Political theory is the study of the concepts in politics. Use this tag for questions regarding political philosophy or scientific theories.
I am less familiar with this tag, but I noticed most of the high ranking questions are more concise. Those questions seem to be about political systems and ideology, so it's probably safe to say that it's a good tag for more academic questions.
others might be of the form "How do politicians decide if they should X or Y?" or "What metrics have been proposed to determine if a politician is doing their job well?" just for example.
Are there guidelines for this, or recommendations?
It's hard to give such advice without knowing what you want to know specifically. I recommend keeping in mind the close reasons. With these philosophical questions, I think you run the risk of asking opinion-based or overly broad questions.
In your first question, the term politician may be very general. One politician may focus on one thing, while another is motivated by something else. You could limit yourself to a specific politician, or you could consider a well-scoped subject. In the latter case, the question might actually be more about the trade offs that come with that subject, rather than the politician making the decision. So instead you could rephrase it as: "what is the trade off between policy X and policy Y?".
As for the second question, you could limit the scope of answers by asking if there is a standard way. Perhaps, "Is there a universally accepted metric to determine if a politician is doing their job well?" is more interesting.
Of course, these are just two examples, and my improvements may not have been necessary (or helpful) in practice. This is just to show how a seemingly broad question can be narrowed down. In the first place, it's up to the asker to consider how to phrase their question. As you can see, there's often some wiggle room for emphasis or even for ruling out an irrelevant concept entirely.
beginner-leveltag. Sometimes long-time users will recall particularly helpful examples, and I'd like to draw upon their experience with the site and the community's evolving response to beginners.beginner-levelyou're going to get, but it's also useful for someone who's been around here for a long time who wants to know about a subject they have little experience with.