Finding relationships between the approaches of the two texts can be done when you are annotating the documents for your analysis. Make sure you look for common techniques but also, specific differences in how those techniques are used. E.g. one writer might use emotive language to foster a positive response from readers, a second author might use emotive language as part of a personal attack to discredit the arguments of the first writer, or to satirise the opposition. You might want to comment on links between the two authors in the same sentence - "Author A's assertive tone is likely to encourage the reader to have confidence in their stance but this could be diminished by Author B's aggressive dismissal of him/her as " a know-it-all." The second document for analysis could also support the arguments of the first one but could express a different perspective on the issue - in a discussion about Vaccination policy, an author who is a doctor might highlight medical and public health aspects. A second author who is a parent, might take a more personal approach to the same issue that supports the first author's arguments.