A good idea is to always try and introduce an original twist. i.e. not "it was all a dream". i did this in the mock and my teacher really liked it and gave me almost full marks.
it is also because i followed a good structure.
present, flashback 1, back to present, flashback 2, back to present.
this will allow you to pick up some good marks for ao1
you should try to using a range of sentence lengths to reflect the mood.
also use metaphors and similes and the like.