I have read and tried many different Urgot builds. But I have never been completely satisfied. After playing around for some time this little build came to life.
Hope the following lines will help you to have as much fun with Urgot than I have, because much too less people play him!

Also this build is designed to play Urgot in mid lane! People will not anticipate you there. But believe me, Urgot is underestimated as a mid laner.

Pros of this build:
-Great last hitter with Acid Hunter
-Great harassing skill with Acid Hunter and Noxian Corrosive Charge starting at lvl 2
-Nice ulti
-Passive helps you to take on carrys
-Fun to play with easy "fog-kills" etc etc



Cons:
-Needs a lot mana
-Item dependent
-Will never become Mister Universe

Lets start off with something really simple. There are not many different rune choices for Urgot. The best way is simple:

Mark Greater Mark of Desolation
Quint Greater Quintessence of Desolation
This will give you some AP, which will increase your dmg (espacially early game) a lot!

Glyph Greater Glyph of Cooldown Reduction
Acid Hunter will be your main dmg source. 2 seconds cd is waaay too long! So get some cd reduction


Seal Greater Seal of Scaling Mana Regeneration
Spamming Acid Hunter will consum your mana very fast. So geat some mana regen runes.



If you are completely new to Urgot and do not have ANY of these runes, then try to get them in the following order:

1. AP (Quint over Mark)
2. Mana reg
3. Cd reduction

You will go best with and here! Upgrade both skills in your Masteries.

is needed in every Urgot build as it is working perfect with your ult. If the enemys are hiding behind a wall / tower / in their base => ult an enemy into your team and then flash out the second after.
BEWARE: as you are very squishy and any stun will kill you, this needs a lot of practice!


Other Options:



Both nice to get some kills, espacially early game.


If you lane mid or often leave lane to gank this is always a good choice!



DO NOT USE:

Urgot is not a jungler... live with it.

Clarity
Already have enough mana reg through runes, masteries and items

Clairvoyance
Your "E" allows to scout everything (even bushes), so do not take this one.

Acid Hunter
Your dmg skill! Do not hesitate to use it, it is cheap and has a low cd. Also get some cd reduction to spam even more


Terror Capacitor
Your only way to slow. Note: Your Acid Hunter will also slow, if you activate Terror Capacitor while your Acid Hunter is already flying.
Very important, as you can increase you slow time knowing this.

Also it gives you a shield, which is why you should pop this as often as possible in late game! You have low hp and are very squishy, big teamfights will be hard to survive.
Furthermore there are enough people that can slow in your team, so try to use this shield in late game without thinking about your slow time.


Noxian Corrosive Charge
Great skill. Allows to harass enemy champs easy. If you hit someone with Noxian Corrosive Charge your Acid Hunter will find them, even though they are out of sigth!
Remember this, as you can kill many enemies, that have already reached their base.

The most important thing here is the ability to scout (even bushes). This will save your life countless times.






Your main dmg source will of course be Acid Hunter, so try to max this one ASAP!
At lvl 2 you should put a point into Noxian Corrosive Charge as this will let you harass any enemy and it scouts bushes!
The dmg from Noxian Corrosive Charge is not important, so max this one last

At lvl 4 you should get Terror Capacitor and max this one out second.

This whole build with all items and masteries depents on Manamune! Whit Acid Hunter you are able to max it���´s passive very fast.
Some items can be chanced, Manamune CAN NOT!

In your masteries put 3 points into "Strength of Spirit", so you have huge hp reggen throuh Manamune.


Always start with:

x2


on your first way back try to get:


Sight Ward x2
x2

Then continue with the buying order listed at the top of the page.

Core Item Build

You will need this items every game. From here you have to decide game by game, what you will buy next.


NOTE:
Different ways will be listed later on!

Thise one is a bit more tricky than the other ones!

First off all you want to get 21 points in Utility!
The benefits from this tree simply work best with Urgot. Then put a second point into "Utility Mastery".

After this you are left with 8 points. Getting "Strength of Spirit" in Defense will work perfectly with the Manamune build. Through the big mana and hp reggen you are able to go mid and rock it.

The last point should be spend in "Deadliness". Now you might ask why simple because you are able to f***ing crit.
Without this no attacks have the chance to be a critical, if you get this every attack has a chance to become critical.
0.6% is rather small, but a lot better than 0%.

And I am aware of the fact, that you will get more crit chance later through Trinity Force, but this will take some time.