1) There is no need to make a full comparison of two (or more) slides on each screen of the powerpoint. According to the theory of information the number of properties that can be shared by any two objects is infinite. You don’t want to drown in a lengthy and pointless comparison exercise.
2) What you need to do is to find one or a few similarities pertinent to the formation of Buddha image in Kushan art. Imagine that you are a detective entering a room where a crime took place. You see a multitude of objects (furniture, dishes, carpets, pictures, clocks, etc). You disregard the vast majority of them and look only for those that were alien to this room, that were moved recently, or that are in some kind of disorder in general. Your first task would be to identify the intruder and you can do it by figuring out to whom the alien objects could belong to. This is what you have to do in this type of art historical research. You are looking for the things that are not known in earlier Indian art: drapery, a non-local manner in which hair is depicted (locks, curls,e tc) and specific hairstyles that do not have a local precedent, facial features which are not know here before. These new (alien) features are likely to be borrowed from somewhere and what you need to do is to go and to identify the artistic tradition of their origin (in this case this would be Greek and Roman traditions).
3) As the next step, you would need to explain how these things could become known to Indian artists. In this particular case you could recall the Indo-Greek period of history with its still missing archaeological record, but with the abundant numismatic evidence showing the local existence of Greek sculpture and consequently of Greek aesthetic ideals. With the collapse of the Indo-Greek power there was another factor — massive Silk Road trade with Rome which undoubtedly brought to India a huge numbers of Roman objects of art. A large array of such objects has been discovered during the excavations in Begram, but the existence of many other types of Roman pieces of art (among them sculptures) can be postulated on the basis of Roman features appearing in local Indian sculpture.
4) Further, it would be good if you could explain why Indian artists were compelled to borrow certain elements of foreign artistic tradition. These could be a result of a void in local artistic system.
5) Finally, you would need to look for the meaningful alterations of images (or their elements) that have been borrowed from Greek and Roman art. In other words, you should point out, you should point out what has been deliberately changed in very Hellenistic looking Buddha and Bodhisattvas in comparison with their Greek and Roman prototypes. To make your work perfect, you would need to explain why these changes were made.
That is all you need to do. Just be a detective! Remember the guy called Sherlock Holmes? All you need is to be as cool and smart as him.
Good luck
