oh hi there I assume you are new at this game since I have not seen you much on this forum but how "new" are you? I have some pretty neat early-game-tactics to show you but its pretty hard to do well if you just bought the game... (Atleast for me it was. It took a lot of time to get really good at the tactics) But I just thinks its much easier to help you when I know how much you've played Starcraft 2 ^^
Here some good basic stuff Try to get a spawning pool built at ten workers. Assuming you scout woith a drone and find your oppoment defence are shockingly weak , your in a perfect opptunity to zerg rush them Failing that your also in a good postion to get a early quuen and build up your eco nice and quick. First overlord over your front door, ESPECIALY vs protosss. If you see a worker unit enter and it doesn't leave, you may find something nasty being built in your base. Having a overlord over your door can lower the chance of that sneak attack by a considerable margin. Zergling make great scouts, burrowed zerglings placed in mineral fiields and other key locations are nice early warning systems. Don't expand against other zerg players unless your prety dam sure you can get away with it. Overseers are prety important as you hit the midgame and changlings a great way to scout, especialy if you sneak one into there base : The giant worm structure is only usefull if it can be set up without being noticed, or for setting up base in distent parts of the map discreatly.
As a Terran player I can really get punished late in the game with Brood Lords if I forgot to get some Vikings out and in the air. Mutalisks are amazing for wrecking or damaging economies. Just watch out if the player's army is nearby and can move out to kill your mutalisks. That, or Missile Turrets/Colonies/Cannons can eat mutalisks unless you have enough to take them out. Roach ambushes are nasty, especially if they burrow+move around my army and pop out. Terrible for my tanks. Fungal Growth from Infestors can give you an amazing edge against Terran ground.
I don't play Zerg, but one advice I can offer is if you're playing against a decent player, DO NOT 14 Hatchery expand, unless you know he isn't scouting you; because if he is, and he's decent, he'll double barracks you and it's over.
