[G] ZvX: Small things that will benefit you

Having Overlords at every base on the map (Including the bases you already have, explained why in section 3), serves so many purposes. Dropping Creep to delay your opponent’s expansions helps significantly. It takes 75 seconds for the creep to disappear once the Overlord is killed. 2nd this lets you know that your opponent hasn’t taken a hidden expansion. 3rd for the bases that you’re going to take you are able to build spine crawlers on the creep, from the Overlord, around your hatch while it’s building! When the hatch finishes you’re able to change that Overlord into an Overseer so that the base is instantly defended from something like Dark Templars.Take notice of the mini map for the sight and creep spread of the Overlords.

I’ve found it useful and easier to execute creep drop when every Overlord you have is on a Control Group. It lets you drop creep from every Overlord at once as soon as Lair finishes. This in combination with Overlords at every base makes for an easy way to delay your opponent's expansions. 2nd benefit is say your Zerg or Protoss opponent goes for Mutalisk/Stargate play early, you can recall every Overlord instantly with minimal clicks and get back to your normal play shortly. 3rd you’re always able to see how many Overlords you have and how many you have building if you add the Overlord eggs to your control group. This will always quickly show you for sure if you need to build overlords or if you just have to wait a few more seconds to start building units when you get supply blocked.

Around the mid game time of ~14 minutes Zerg is economically strong enough to start investing in more static defenses. Putting Spine Crawlers at every mineral line is necessary to stall harassments long enough for you to respond. Remember the Overlords at every base? Now you can turn the Overlords at your established bases into Overseers. This is EXTREMELY important to have mid game versus Zerg and Protoss. Instead of using another drone for spores that can be picked off by something like DT’s, the Overseer is untouchable by any type of detection focus fire from melee units. Also the Overseer is mobile so when the DT’s run or Infestors are burrowed in your base, you can seek them out. The combination of Overseers and Spines at every base is a way to keep you from losing games to small harassment and stall larger threats throughout the game.

This is something so many Zerg players do not understand so I will explain it in great detail here. When Mutalisk are vs other Mutalisk getting +1 armor is far better than getting +1 attack. Every armor upgrade in the game gives a full +1 damage reduction to the unit. Now mutalisk have the glaive attack which as you know bounces to three units. Every time the attack bounces it loses some damage output. So for example, without any upgrades the Mutalisks first hit does 9 damage, then the attack bounces to a second target doing 3 damage, lastly the attack bounces to a third unit doing 1 damage. Getting the +1 attack upgrade does NOT give +1 to the (9)(3)(1). The upgrade is distributed like this, 9(+1), 3(+0.333), 1(+0.111). This means that by the time you have upgraded all of the attack on the Mutalisks, its damage is 12, 3.999, 1.333. So by the time the attack has been fully upgraded this means that the 2nd bounce on the glaive has only gone up 1 damage point! Something that the first armor upgrade will negate. In my examples, +1 Attack Mutalisks on the left and +1 Armor Mutalisks on the right, you can see that when 6 Mutalisk are vs 6 Mutalisk the armor wins every time (having no micro) with a significant amount of left over Mutalisks and for a 2nd example I've done 12 vs 12.
Here is the 6v6 battle.
This is the 12 v 12 fight.A trick in Mutalisk vs Mutalisk fights is keeping a group of Lings underneath your Mutalisks. The Lings soak up some of the bounce attacks from the enemy Mutalisks. In close fights, this will decide the winner.

Map vision is one of Zergs most potent advantages. Not only seeing every base on the map with Overlords but also seeing all the dead air space where drops will pass through is very important so you can react as early and effectively as possible. Having your base outlined with sight and creep is important and Overlords serve both of these purposes effectively. By outlining your base with creep you can place down some well positioned spores to shoot down drops,scouts and stall larger air attacks. Keeping Spines in range of all your Spores will assure to stall or clean up anything that does manage to get dropped before the transport dies.Notice the vision the Overlords give you around the map, the Ling placements that are closer to the enemy and the map vision/defenses around the outer sides of your bases as shown.

This is further extending the advantage of map vision for Zerg but in places that are too vulnerable for Overlords. The first and most important place is outside the enemy base. Have 1 Ling there to see and alert you of enemy army move outs. This will give you more time to react correctly opposed to an army surprising you at your base or the Naga tower. Now in places where Xel’Naga towers have no vision such as the back pathways on Entombed Valley, a Ling can keep you from being surprised and out of position from harassment forces or main army movements.It’s your choice to use either burrow or patrol. Patrol gives more sight in the area and will more likely be attacked and alert you, therefore increasing the chances of spotting enemy units’ movements, but burrow can still spot the enemy and more importantly not let your enemy know you know where they are. Also it can spot if the army changes direction and/or retreats where the patrolling ling that died, cannot. This is simply player preference on which to use.

So important! Unit movements are maximized with the creep for Zerg. Defending bases off creep with units takes far too long so use your Overlords creep or the creep tumors to keep your bases synced together. Getting in position is one of the most important factors of the Zerg race, being highly responsive to opponent’s army compositions and movements. Creep connection will make the difference.

2 things here, creep drop and a burrowed Ling will drive your enemy crazy. (Thank You to Belial88 for pointing this out) Hold position on the Overlord when over a base will let it drop creep for a while longer while its being attacked. This is very useful with slow Overlords especially. If you have gotten the speed upgrade it is up to you whether or not you still want to sacrifice the Overlord for a few extra seconds of creep dropping or if you want to run it away. When they do kill the Overlord and the creep finally dissipates, they still won't be able to expand because of the burrowed Ling. Terrans might waste a scan for a 25 mineral Ling, unquestionably a positive for Zerg. Protoss either brings back units with an observer, which takes a bit of time. Otherwise they wait for the pylon and cannon to finish, so it can kill the Ling. When SC2 requires so much attention and multitasking everywhere, this little tactic will annoy and distract your opponent greatly. Also the Ling gives you time to get another Overlord there for more creep dropping or place a Nydus if the enemy army is far enough out of position to allow the Nydus time to spread its own creep.

Somewhere around 20 speed lings always in position on the map ready to harass and stall army movements is a very strong tactic. A careless opponent will lose worker lines when they over extend their army. Even if your opponent is covered on all fronts the lings can pick off scouts, proxy pylons, creep tumors, and any other vulnerability your opponent has. There is almost always something for these lings to kill. Even at pro levels you see ling run bys’ doing significant damage that can swing the game into the Zerg favor heavily. You can honestly use any units for counter attacks like a small roach force, but lings are obviously the fastest, cheapest and usually the most efficient way to do so.