umm..... well, im no expert on essays..... i mean, to me there sometimes isnt really much difference...
but well, here's my advice...
in a drama essay, remember.. i know it sounds obvious, but its a DRAMA essay.... many people tend to be so used to writing english ones, that they adopt an english style essay for the drama one.
you do not need to use words such as "responder" or " composer"...etc....just protagonist/antagonist, central character, playwright etc....would do.
also, remember DRAMATIC TECHNIQUES...and how this affects the audience..
im so sorry if you knew all this already, but you'd be surprised at how many people there are out there who dont know how...even worse.... many who do not even realise that they're totally missing the whole point..until they get their marks that is!-pah!and even then.....
it also really depends on the question, and what your focusing on.....