How should I start my rearch paper? I'm trying to prove my point about Macbeth being related to the ambition of some politicians in our times.
This is an interesting topic. I think this can take you in many different directions. As far as the Macbeth side, the book is really all you will need to support Macbeth's ambition.
I believe that most of your research will need to be on different things that Politicians have done to show that they too will do anything for a position. You can look at something as simple as the money spent on campaigns, to something as complicated as making false promises and bribary. I don't know if you will get anything on the side of murder to gain a position, but you never know what you may find.
If you include dictators in your definition of politicians, you might start with Parade magazine It runs an annual feature story listing the ten worst dictators. I think this might be a good place to start; you may find many parallels between Macbeth and these dictators.
Another somewhat contemporary dictator who bears some resemblance to Macbeth might be Idi Amin. Good luck with this intriguing topic.