Zerg should always have twice the expantions of the other races....if your ennemy has 1-2 expantions..wich he shouldnt have vecasue if he does you did a bad job...but anyways, if he has 1,u need 2,if he has 2..you need 4,with zerg, you have to learn to control the game...
example: vs terran,wich is the hardest matchup, you attack him early with lots of lings, he should be contering with firebats..you know he will do that, so your plan was to get a few lings,thens tart massing hydras,wich owns firebats.
The game is not really about your build order or what unit you get, its when and how you attack,conter,defend...... Well i could go with this for hours..i trained a couple of players on b-net, and they are doing pretty good right now.
Im into war3 lately..but if you guys want to game sometime,just pm me.