Hi I just did my viva voce for my History EE so here are some tips that might be able to help you. First of all do not underestimate the amount of research you have to do, a good EE has 20-30 sources and much more background research that isn’t even cited. Make sure it is structured like a normal history essay would be: context, arguments for and against your research question. Also try many many drafts!! My first rough draft was 7500 words, but by doing it again and reading it over again and again before getting feedback from your supervisor so that you can get the best needed feedback that Willa actually bump your grade up instead of things that you could do yourself.