This is my first guide. Though I'm not so experienced, please take it easy.

This build stands for a pushing specialist, which cause hardcore to your enemies's defense line. Most of the time, you will make it to their keeps.

How about your enemies pay attention on you? Creep Tumor and Nydus Network is on the play.

Mecenaries? They should obey your pushing command.

If you are expecting a backdoor hero, Zagara is one of the best choice.

In my opinion, this build would be far more effective than a pushing Murky or Azmodan in most play.

Centrifugal Hooks Other talents seems not so good, but this one will help you push from afar. Safety first!
Tumor Clutch More creep expansion for free!
Volatile Acid More damage give more destruction. Just in case you feel insecure, go for Endless Creep
Nydus Network A best teleporting portal. This is the key of your destruction, place it whenever you have a chance.
Bile Drop Give you tons of damage on structure. If you still need some more insurrance, go for Spell Shield
Baneling Massacre Double banelings, double fun! A squad of banelings will crush a tower or health pool in one cast.
Broodling Nest Push game has never been this easy since everytime you travel with an army. However, in most cases, Bolt of the Storm is a better choice cause a death at level 20 is a real pain in the ***.

Tomb of the Spider Queen 3 lanes, easy lane travelling and many hidden places for Nydus Network
Cursed Hollow 3 lanes with many mecenary camps, the only disadvantage is the curse require combat
Sky Temple 3 lanes and lots of hidden places, but sometimes you need to join combat
Battlefield Of Eternity 2 lanes, but most of the time, the Immortal will not push as far as you
Dragon Shire 3 lanes, every lane require a campsite, this is a buff for Nydus Network

In ranking, most players would pick a heavy combat team with 1-2 warriors, 1 healer and 2-3 assassins. Specialist is barely picked.

So if your enemies got real heavy combat, except Tomb of the Spider Queen, DO NOT build it this way.

Most Zagara build require talents, which causes her to takes time to level up. Below is my frequent choices at early game.

At level 1, DO NOTHING. Just simply stay in your lane, breed some Creep Tumor but don't use skill often. get exp and level up. Or join your team if they need help. This is understandable since heros got low damage at low level.

At level 4, now you could lays more clutch due to Tumor Clutch, use it anytime anywhere, this is a big advantage that help you gather more sights, push your enemy back or escape from gank easier. But remember to save your mana for later use

At level 7, Volatile Acid is a plus for your power now. Anytime your enemies is push behind gates, unlease your banelings and infested drop to crush their defense. But don't use it on forts because it's quite tough

At level 10, places Nydus Network in dead ends, bushes, hidden corners or just behind your defense lines, this would help you travel really really fast to spread your destruction.

This is important, place one Nydus at home, this will grant you the ability to teleport, push, regenerate and loop through it again.

For example, when you first upgrade Nydus Network giving you 2 charges, place one on top lane and one on bottom lane. When enemies is not around or enemies can be push back easily, move to that lane, unleash your swarm. Seems easy, huh?

One note you should take is do not always unleash your banelings on structures. Sometimes you can use it to swipte out a wave of minions to make ways for your minions. That would be more effective cause you can stand and fight with them.

To push an enemy back or to defend yourself from gank, unleash your Hunter Killer, they are very useful.

If your enemies is go together to push one lane, it's your high time to place more Nydus Network and teach them what is the real push while your team is trying to slow them down.

In most situations you are free while your enemies have nothing to do, take some mecenaries. You can do it alone with tanky Roachings and massive damage Banelings.

The game will get harder when your enemies pay attention on you or you have make it far enough to their core, when their numbers of keep reduce to 1 or 2. This is the time to show yourself, how well you place Creep Tumor and Nydus Network, how well you escape from enemies's claws,... are all told here. And I leave this part to you.

1. Always remember to place Creep Tumor and Nydus Network, use it wisely.
2. When you want to push tough structures like forts or keeps, it is more effective to use your ability to clear minions first.
3. Never push the core alone when it is highly shielded.
4. Mecenaries will helps you a lot
5. You can get inside Nydus Network safely if your enemies don't have stun or knock back. Once inside, if you have another Nydus Network even if your current Nydus is destroyed, you are safe. If no, only death awaits you.
7. Don't rely too much on Nydus Network, sometimes you can escape with Bolt of the Storm leaving your Nydus safe.