A good comparative essay should firstly and always address the question that you have been asked. You could either approach the essay question paragraph by paragraph, where you talk about the subject of the question in each paragraph and you end said paragraph with comparing the respective texts. You have to make sure not to drift into narrative, read over your answer and if it is telling the story over again then you should include more analytical and critical comments. These are crucial to writing a good comparative essay. Alternatively, you could write each paragraph as a comparative one in order to avoid not having the problem of linking the two paragraphs together. This could be a better approach depending other on the question and how you like to write. You must address the similarities yes, but it is important to address the differences in the texts in order to draw a good conclusion. The contrasts are something that the authors have deliberately put there, so that their individual meanings are taken into account which should not be ignored.