well... there are a few thinks:
first of all: your micro. if you micro your units good, half of the work is done. the other half would probably be your deck/strategy. So its important to know how to micro good and you can only do it good by practice.
another thing is for maps to know where fire dancers can 'cliff dance'. This way you will not be surprised and overreact/underestimate it.
it is also nice to know what are the strong parts en the weaknesses of certain decks, for example: pure fire has great M counters in T2, but also has a lot of M units in T2.
Also practice to know what card to pull out when you try to counter something, so if you play pure fire and you see a night crawler, you immediately play a drake or enforcer to counter it (this is also situation dependent)
and just to make sure: i'm not a pro either, so things might work better or worse for you...