Welcome to Nazeebo Town! Population: YOU!
Starting off with Death Ritual provides you with an uncapped HP/MP stat.
Focus on tagging dying minions with Voodoo Ritual, whether it's with your abilities or with an auto attack.
It is imperative you try and get as many as you possibly can - it makes you incredibly sturdy and helps you spam your abilities.

You're a lane bully, especially if you can combo your abilities.
But you're also just a tad bit squishy, especially if you don't have your Zombie Wall - it serves as both an offensive and defensive weapon. Look to use it to save your allies and destroy your enemies.. or annoy them, that's good too.

TIPS:

• You can always try and bait the enemy team into killing you near your own gate of doom.. Simply walk out, bait them towards the gate, and once they think they've got you.. trap 'em with your Zombie Wall, destroy them with your Frog & Spiders and watch as the towers truly tear into your enemies.
• Stand up as close as you possibly can when releasing your frogs upon your enemies. Since the Plague of Toads is a conal ability, the closer the enemy is to the release point of the frogs the more frogs that will hit them. The Plague of Toads ability has a fantastic damage rate, but it's only if you land a majority of them. You can ensure this if you can trap your enemies in the Zombie Wall.
• Your Corpse Spiders has an initial hit damage and a minion/continuous damage. Wherever the pot breaks, will be damaged for x-amount initial damage, and the spiders will continue the damage when they're broken out of the pot. So try and capitalize on the initial throw.
• If you're up against a melee comp, you can use your Zombie Wall to not only trap them, but you can create a shield around yourself if they cannot capitalize on it.

As for your second talent, you have two choices - entirely dependent on your opinion.
While Gathering Power is a powerful (PUN INTENDED) choice, Envenom is just as fantastic, especially if you aren't that accurate with your skill shots. Envenom will also enable you to 1v1 even better than Gathering Power. But, in the long run, Gathering Power will get you more bang for your buck in most situations where you can not only land your skill shots, but also position yourself very well.

Welcome to a whole new world. In mid game you're able to dominate all beings! (except for those pesky people who help other pesky people stay alive..)

You're pretty much doing the same thing you were doing in early game, but with CONFIDENCE.
Everything here is pretty self explanatory.. But I'll go over it just a bit to show you some "other routes"..

NOTE: I'm sticking to the Ravenous Spirit build, so no expansion on the Gargantuan because it's just poop as it pertains to the intent of the guide: destroy teams.

You have two choices for your third talent..
Gidbinn or Fresh Corpses.. I would almost always go with Gidbinn, because it is a better choice overall, no matter the circumstance. However, if you're going with a Zombie-esque build, you will want to go with the latter so that you can later have your fire-and-forget Zombies.. Refer to: Dead Rush. This is more siege-based, I would say though. So, what have we learned? GO WITH Gidbinn UNLESS YOU'RE A BAD PERSON.

Heroic Ability
Now, we move on to the ever controversial heroic ability choi- who are we kidding, folks?
Ravenous Spirit is our god, our future, our dream.. May the Ravenous Spirit be with you.
Remember that Ravenous Spirit isn't a right click to attack ability.. It is an AoE, controllable minion of EXTREME DAMAGE. It does the same damage to all enemies hit, and will destroy an entire team during a teamfight. Just remember, you are stuck channeling the beasty unless you cancel, are interrupted, or finish channeling him.

As for your fifth talent, you have a few choices.
I suggest Rewind for obvious reasons. More zombies, more frogs, more spiders - more damage, more death.
Note, however, that you cannot summon another Zombie Wall until the first wall has expired or has been canceled. Some players will choose to go with Sprint for survivability/catching opponents.. I have already talked about the Zombie route.. (Boooo..) But there is also one more route: Toads of Hugeness despite the terrible name, the ability itself is not all that bad, especially if you're a little scared to get close to your enemies or are looking to siege. Just remember, if you go with Toads of Hugeness you're partially committing yourself to using your toads at max range.

So you've basically killed everyone on their team like 32 decillion times.. But whatever, you've decided to drag out your enemies' defeat, and really wrack up some experience so you can quickly get to that delicious Nazeebo master skin. For some reason, Blizzard just keeps giving you more stuff to choose from- BUT HEY, we're okay with that.

The only real choice for your second to last talent is Specialized Toxin. The others are alright, but for the purposes of this guide (killin' peeps!) it is the cream of the crop.

The real controversy or mind-wrack (no shadow priest puns intended) is for your final talent choice.
Here, there are 2 valid choices - and both are pretty detrimental.
Annihilating Spirit or Bolt of the Storm. If you're really destroying the other team and want to destroy them some more, go with Annihilating Spirit. On the other hand, you can go with Bolt of the Storm to really create some hilarious plays..

If you're finding that the enemy team is really targeting you in teamfights, and you're not confident in your team's ability to peel or your ability to position yourself, then go with Bolt of the Storm. Otherwise, go with Annihilating Spirit.

It's truly up to you (as with all decisions) to decide what is best for you.
Good luck, and get to destroying some teams.