With Urgot, you can stack manamune faster than ezreal. Although Urgot's W is only 50% on hit damage, you can use a combination of toggling W and auto attacking to Maximize Urgot's DPS (This video will tell you how to: https://www.youtube.com/watch?v=Tklfwg0HbCI) and his non-W auto attacks will get the on-hit damage. Also, this combo works well with the second item in the build, iceborn gauntlet, which you can proc the spellblade passive with the toggle of W. Although you will be squishy in lane, iceborn gives survivability and when you get frozen mallet 3rd item, you'll be unkillable. Deaths Dance forth item gives you the lifesteal (adding onto the bloodline) to become a 1v9 monster.

Your goal is to survive lane so you can rush Manamune and reach your Muramana Iceborn powerspike. Urgot sucks with tear only, so make sure you back for a Pickaxe, this will give you damage to kill your laner, but watch out for being squishy. If its a hard matchup, try going for defensive items instead of buying tear first (like armor for boots, refillable, etc). Try to get a second back Manamune (1525G), but you can also go tear and sit under tower. To stack tear, make sure NOT TO UPGREADE LVL 5 W. Spam your lvl 4 W and Q in lane. Your w autos also proc manamune(but not tear). Since lvl4 W is 3 seconds cd, you should aim to have it stacked by 20min.

Muramana, Iceborn Gauntlet, Frozen Mallet, Deaths Dance, Guardian Angel, Defense Boots
With every item this champ scales harder and has a chance to win fights against champions like Camille and Jax with full build. You will be squishy at 2 items, but your 3 item powerspike is what you should be playing for.