How to beat a pro at SC when you're a complete n00b ( worked for me, the onlly time I played SC on battle.net ):
Make lots of hydralisks and even more zerglings.
Upgrade them to max, bury them where the enemy is supposed to pass.
Resist the urge to unburry when a few troops attack your base, let your defenses deal with it.
Lay hydralisks on the map, from places to places, to keep the scouts at bay ( the ones that can see burried stuff, I was against protoss iirc ).
Simulate an attack ( big enough to be convincing, but not big enough to stop a counter attack ).
Unburry everything when the enemy is right into your zergling field

Destroy what's left

Has been so efficient I couldn't believe it
