And the golden rule about wind ALWAYS blows from heading to track - I am amazed the number of students who aren't aware of this key fact.
As Phil said make sure you know your way around variation and deviation and which way to apply it - this is another weak area.
81% you are heading the right direction, nice to be up to around 85+% and under exam conditions before you sit the real thing, this should allow for a bad day at the office.