Firstly, you'll want to pick out the key words of the question and define these; here the presentation of "evil" in the monster is what the question is wanting you to focus on. Also, Importantly, "how far" is key to consider; this requires a judgement: Is the monster solely evil? Does the monster exhibit more humane qualities? Then you'll want to focus on the ways in which Shelley is creating a sense of evil to the character (for example: physically, linguistically, gothic setting). Also, you might want to consider a way in which the monster is in fact cast in a more humane light (For example: his interest in literature, his desire for sympathy and companionship). These considerations will then inform your essay structure. For example, if you are answering that the monster is ultimately evil, your introduction will establish your line of argument; ie. how far the monster is presented as evil. Moreover the introduction should define the keys terms of the question as well. You will need to make sure that you are maintaining your line of argument throughout; this can be done by making sure you are linking all your paragraphs back to the question and what it is asking ("how far"). Your first / second paragraphs, therefore, might examine the extent which the monster is cast as evil - physically (paragraph one) / certain actions (paragraph two). (There are lots of themes which feed this notion of evil, however, it is important to stick to the question and focus on less in detail so you don't stray off topic). You then might go on to examine the counter argument: how, in fact, the monster has developed more humane qualities which take him beyond his "monstrous" and "evil" exterior. You may want to insert a comparison between the monster and his creator here to showcase the blurring of boundaries between monster and man (quintessentially good and evil). Alternatively you could look at the monsters desire for companionship and sympathy from his master; this highlights his more vulnerable and infantile nature. Then you would want to conclude, summarising your judgement on how far the monster is presented as evil.