I was having problems with this at the begining of the year, I could get my answer up to Band 5 when i fixed my argument, but couldn't push it over to the 6. Make sure that when you write your answer, you have a single line in your head of what your argument is. When in an exam, write it on your paper below the question. If I look at my HSC paper, Ive got my argument in one consise sentance which i refered back to and a plan.
The issue with band 6 was that I couldn't get my detail up to scratch. The critera for a 6 require detailed historical information. I overcame that by changing the way i wrote points in an essay. It ended up being something like...
ARGUMENT
Explain
DETAIL
Argument
And it would go like that for every point I made.
I ended up with 91 in the exam, but only wished I learned all this so I could have done as well in assesment.