Link

If you do any kind of comparison question first find the issue. There will be two large issues, one that both sources agree on and another that they disagree on. Find both. In fact look along the lines of things like causes,effects,extent or degree of impact and perspective. It is usually along those lines.

If you are really lost,then look at what is the overall topic first then ask yourselves this question.

Are they saying the same thing?

Are they saying anything in slightly different ways of making different points on the issue?


Look there first and establish the issues before you proceed. It will help structure your answer.
Also,

Don't forget the linking words such as similarly,also,supports and however,whereas, in contrast, contradicts. Using these words give the examiner the fact that u know and can spot the similarities and differences. NEVER use words like saying about or one says this, the other says that. Be clear and use the linkages.