The Zerg economy is pretty different then the Terran and Protoss economies and a good Zerg player will use this to his advantage. Terran and Protoss are generally a little stronger at teching up then we are so we have to find another way to get the advantage. This guide will show you the basics of mastering the Zerg economy.
The first thing we need to realize is that the only way to keep up with a strong Protoss or Terran player is to have a larger mineral and gas intake then they do because our units will not be able to stand toe to toe with them so we must out produce our opponents. StarCraft 2 gives us some advantages in this area and makes it easier for us to expand. The hatchery only costs 300 minerals where with Protoss and Terran it costs 400 minerals to expand. Also, we make all our units at the hatchery so there is no need to build a bunch of new barracks or gateways like our enemy will have to when they expand.
I recommend expanding very early on in the game when you are just starting to build a few zerglings. You should have some extra minerals at this point and you can either use them to upgrade to a lair or expand. In some cases it would be wiser to upgrade to a lair if you need to get some anti air quickly or you are doing a muta rush but most of the time I would not recommend a fast upgrade. Again the key to winning as a Zerg player is out producing our enemy, which means we must expand fast and often while at the same time keeping our opponent from expanding. If you can master this part of the Zerg game then the rest is easy. Tech New Master