A very important thing with Ancient history and essays is that the implications of certain events need to be noted down! It is integral to the focus, as analysis and evaluation comes to play a role that is best enacted through a distinct point that is being made. Without a foundation the structure crumbles, its the same as an essay, without content l fear your without an essay that includes credible and plausible information, thus losing marks is no rarity.
So, l guess advice for any Ancient history student would be to include the implications of events, an analysis of the implication along with a possible evaluation of events coming to pass, if need be. Believe me l practice this often, and l've heard no complaints from teachers! Also full marks are a guarantee when you have numerous quotes backing up your statements from both historical and contemporary sources, para-phrasing doesn't hurt either, if you can't remember an entire quote, don't try to rip it - make it up - these people are HSC markers, and l'm pretty sure that they know their shit from clay!
Good luck! don't study to hard...... coz l'm still going to Ownz you!