well strategies all come from the fact Zerg are *reactive*. As in, you see what they have, and react. Or on some ocasions, pre-empt.
So ZvZ, most common attack you'll recieve is baneling/zergling rush, I have a replay at home, but 4 roach's on the ramp like this:
Code:
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R R [spine's here for good luck
R R [
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Roachs can take 2 blasts from banelings, and the splash distances isn't big enough to hurt all 4, stick 2 spine crawlers on the top, and you can not worry about zerglings/banelings and tech up, although you wont be able to expand. Most zerg players will keep firing banelings at you, if you choose to do baneling rush, do it once MAYBE twice, any more after that are wasted minerals/gas.
ZvT, hardest of them all, terran are STRONG. The most common tactic I face is marine+Marauder and sometimes Medic ships. Simple fact is, there isn't a great counter, I find mutalisks are the best, but, you can't let them get that marine/marauder ball going. There is no defence. Simple. (hence why all the complaints of terran being OP). If it does come to that, generally broodlords, mutalisks, and infestor gas stoppy thing (forgot its name here at work
), ultralisks, but they get eaten up by marauders/focus fire. So, scout them HARD, sacrifice overlords occasionally, if you see 2 barracks, 2 factories with tech labs, its marine/marauder, if you catch a starport, medics too. If you see reactors, they're going to spam marines. Thors are hard, but using mutalisks in a smart way (see my previous post) can sort that out, siege = mutalisk, vikings = mutalisks, etc. see why i like muta's
ZvP, 2 common tactics, 1 with a variation, voidray rush, easy to see, toss player will usually turtle up with loads of cannons and you'll see an early cybernetics core, sometimes they'll put the core at another part of the map, so spread the overlords far and wide, sticking them on cliff face's is a smart tactic. Void ray's is simple, spore/queen/mutalisks. 2 queens can pop 2/3 void ray's, even more if you transfuge in a smart way.
Now, 2/3/4 gate rush, and warp gates. DEAD easy, I've had toss player put 4 gates outside my base, and i defended for 10 minutes while i just teched up to muta's. Do a regular build, and make sure you get 6 lings fairly soon, zealots will turn up soon, so you need to put 2 crawlers down when your spawning pool pops, the lings and queens should be able to defend any really early rushes, play chase the drone if you have to. Once you've got the crawlers up, spread creep for the ramp, and block it with roach's. And thats it, tech up to whatever you want, make sure you have a couple of spore crawlers for the inevitable cloakers, but I find most Protoss players seem to commit quite heavily into 4 gates with stalkers/zealots and wont change their strategy until its too late.
Infact, thats the beauty of zerg, you're so used to having to evolve to each situation, that you'll find terran/protoss players go into a game with a set strategy, and will keep firing that at you until they lose or win. Never do the same thing 3 times in 1 game.
Finally, MACRO. For every 1 base your opponent has, you need 2 or 3, especially with muta's, i find 2 fully saturated mineral lines needs at least 6 geysers with 3 drones to keep the mineral/gas ratio happy. And keep the queens spawning, if you do get wiped, theres nothing like having 30 ready to pop into whatever you want straight away. Thats the main advantage of zerg in the late game.
I can go 200/200 down to 90/200 in 1 attack, and be back to 200/200 in 1 unit cycle. POW
Hope this all helps you zergies, I had a big losing/learning curve which is horrible, stick with it. When the game does get balanced, you'll be a much more rounded player for it