By an "aesthetic issue" I mean an issue in the philosophy of the arts.
The topic questions are a kind of list of aesthetic issues. There are many more that could go on the list. But what puts something on the list, or keeps it off? How do you know that you have identified an aesthetic issue to write about in your critical essay? There is no precise answer to this question, any more than there is a precise answer as to what is an appropriate topic for conversation at dinner. And still, some topics are appropriate and some aren't. Since an aesthetic issue (as I'm using the phrase) is an issue in the philosophy of the arts, it may help to know what philosophers do, what counts as a philosophical issue. Philosophers tend to do several things.
Philosophers look at arguments, to see whether they prove what the arguer says they prove. For example, if someone says that the mass-produced paintings at Ikea are not art, a philosopher will ask what reasons the person has for saying this, and then try to see whether the reasons should be accepted, and whether if they are accepted they are good enough to establish the conclusion.
Philosophers uncover assumptions. This is closely related to examining arguments. For example, in the case just mentioned, the person who says the items in Ikea aren't art is making some assumptions about what counts as art. These assumptions may not be out in the open; even the person who is making them may not be very clear about what they are. A dialog of questions and answers is often a good way of uncovering such assumptions. Since the days of Plato, this kind of dialog or dialectic has been an essential philosophical tool. The point is not to get rid of assumptions; it is not actually possible to think without making some assumptions. Rather the goal is to show what the assumptions are. After that, of course, if they can be shown to be unjustified or unnecessary, then they will need to go.
Philosophers analyze concepts. So, for example, a philosopher of art might ask what makes something delicate, or powerful, or sad, or boring, or scattered, or unified, or exciting, or harmonious, or even beautiful (this last concept may really be too big for helpful analysis, but lots of philosophers have tried all the same). There are many ways to analyze concepts. In the essays we will read by Larry Shiner, the author switches from the sort of "timeless" analysis that philosophers often do, where you just try to think about what the content of the concept is, to an historical analysis (how did we get the concept of art that we now have).
Philosophers build theories. So for example, Arthur Danto has a theory of what the essence of art is. He has been developing the theory for about 25 years now, and it has become one of the most influential theories in the philosophy of the arts. (See the essay on Danto in Philosophers, Artists and Critics on Art for a summary of his views.) You may want to start building your own theory about something. You probably aren't ready to do that; but you are certainly able to think about and respond to the theories that other people have built. There are many ways to build theories. One of the most important things a theory builder must do is to determine the kinds of analysis he or she will use, and what will count as an illuminating explanation. For example, appreciation of art works is rooted in human biology in various ways. In your theory, are you looking for explanations that take things back to biology? Or are facts about the biological basis of aesthetic appreciation relatively unimportant, not facts of a kind that might be used in a serious explanation?
Philosophers start with the sense of wonder, and press its questions as far as they can, trying to find satisfying answers.