Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Build still in progress.
Start of game:
Grab a Dorans Ring and a Mana Potion, or a health potion if you prefer.
You'll need the Mana Regen and the Extra AP for harassing with your E.
As soon as you hit level 2 this is where your Mana Problems start.
Try to let the enemy champ, assuming you are Mid, push as close to your turret as possible. This way you can bomb them and start throwing your blade, chainsaw or crab pincers, at them longer. At level 4 this is when you really want to let the enemy push. When they are near your turret this is when you have the upper hand. Pop your Shield up and throw a Charge at them, I usually position the circle behind the Enemy Champ. Once they're hit that when you want to move your cursor over them and Start Spamming your Q. If you see you're running out of mana, use Clarity. They have a long way to run to get away from you and they are slowed with every Acid Hunter you hit them with.
When you reach about 2.5k gold this is when you want to head back to base. Grab a Bilgewater Cutlass and Level 1 Boots. You should be Level 6 by then and this is when you want to start ganking. Ganking with Urgot is a bit difficult.
Hide in the bushes from top/bottom. Pop your shield, Throw a Charge and Start Q'ing. Your team should be already attacking whomever the target is and you should be running towards the turret while throwing your Q if the target is still drenched in Acid.
This is still a build in progress. bear with me >_>