PROS
+Strong Ulti able to 1-Hit KO enemy carries like Ashe,Miss Fortune etc..
+Ulti can be strong from very early if you have the Sword of the Divine Ready..
+Hero has high Durability.
+Hero has high Attack Speed.
CONS
-Summoner must not be a coward..
-Summoner must know how to jungle..

Warwick is a very strong hero.He can call himself king of jungle and suppresion.He can be very effective if he jungles than if he is in a lane.

Since you are going to jungle you should take smitein order to bring down the Golem and get the blue buff faster.
For 2nd Summoner Spell you can take:
Ghost- Its good for getting close to the enemy doing ulti and running away after if you want

Flash- Its useful for a quick escape after you have done you ultimate or a quick charge.But ghost is more recommended.
Ignite:- Cast this before your ulti to enemy with high hp regen to deal more damage to him.

For runes it is better to pick Attack Damage Marks,Seals,Quintessences for better Ulti and some Attack Speed Glyphs for better jungling.

Items must support Attack Damage , On attack effects and Some Health for Durability.
Start with a Cloth Armorand 5 Health Potions...
Go get the Blue Buff using your first skill and Smite.You can use your pots if you need.After go clear the Golems or Wolves or Wraiths.After that your smite will be recharged and you can go take on the lizard.Kill the lizard and exterminate the two remaining camps.Then recall to your base.Get Sword of the Divine. Dont forget to finish Berseker Greaves and Madren's Razors.Go and kill a carry . Carry on until you have finished this build. You are mighty. :P

With this Build (It looks like a normal build with just an extra item). I have tested the item and saw with my eyes that every four hits the ulti was doing 100 extra magic damage was dealt to the enemy) Try it yourselves.
Before you charge with your ulti make sure you press to deal the maximum damage.