The idea of this build is to lane with Warwick and grab buffs from your jungle and the enemies jungle. The best lane for this is bottom lane and if you are blue this is even better as you can steal purples blue buff from there, to muck up your oppositions jungler and their pattern. To further do this make sure to leave one of the small lizards still alive so that the rest of the camp doesn't respawn.
Use your position on bottom lane to steal the dragon from when you have your Madred's Razors and Vampiric Scepter. If you are in lane with a Caitlyn or Ashe or other ranged physical champion be sure to spam your Hunters Call whenever they are attacking a turret, player or even just clearing a minion wave. Also remember that even if you aren't attacking a tower but they are, use it and give their damage output a boost.
Finally keep a close watch on your opponents health, once they will die from your ultimate, use it. Even if they are under a tower still use it. Because they will die quickly and you regain lots of health you should survive the dive. However be sure to note if their teammate has a slow or stun and if they do be careful when doing this!