Jungle WW since his buff is really strong now. The passive buff he gets allows him to do damage while building tanky also allows him to clear the jungler a lot faster. There are some counters to warwick but the pros outweigh the cons on playing warwick for jungling.

I chose the yellow armor runes because it is the classic rune for junglers. Less damage you take the more of the jungle you can clear without investing so much in hp pots etc. The attack speed runes allow you to compete against other fast junglers and most of warwicks damage is from auto attacks. The more often you attack the more damage you do especially from his passive buff.

You are probably wondering why I go 15/15/0. Warwick does attack damage and magic damage btw. The magic pen and armor pen allows warwick to do a lot more damage. You build warwick tanky so that is why I dont go all the way down the defense tree. Plus with the masteries and runes you have around .9 attack speed at level 1 and 1.2 attack speed with your W.

There is multiple ways to start with warwick. If you like to counter jungle against a slow jungler such as amumu you goand some . You ward his red and take it when he is doing it but lets say your team doesn't need you to gank before your 6. I would go and rush to 6. I normally dont go back to base until I can afford madreds and level 1.
The wits end allows him to do damage and gives him MR for being tanky for intiation. Wriggles allows warwick to have armor and attack damage. Frozen heart is good for warwicks low mana pool and it also slows enemy attack speed down. Spirit visage allows you to heal up more from everything and reduces your CD which helps in teamfights. GA I get because with this build I am like a raid boss and they cant kill me easily. The revive from GA really makes them waste their time damaging me. If you are versing a magic heavy team then I would go instead of . Only reason why I would get a bloodraiser is if they are super tanky and my team lacks dps then I will finish my last item with bloodraiser otherwise dont get it. Bloodraiser is a luxury item not a need.

For rank play Warwick is a strong choice. He works really well with anyone that can stun in lane. If you have a Kennen, sion, veigar etc. easy mid lane ganks. For top lane anyone with some CC warwick is a guaranteed gank kill. Ashe on bottom lane works really well with warwick. Warwick is strong for being able to solo baron because of his burn damage. You can also do an early dragon. Your ganks as warwick will be weak before level 6 if you dont have red buff. I encourage you do gank if the lanes are losing. If the lanes are stalemate please just rush level 6 then start ganking. It pays off once your 6 trust me. If a lane is losing get red buff and gank their lane accordingly.

Warwick is great to play if you are new to jungling since he has a lot of sustain. You start at wolves then blue then head over to the wraiths. After the wraiths do red buff then golems. For doing the red and blue buff make sure to bring them into the bush to prevent other junglers taking your buffs. You can easily do dragon and baron as warwick. He is one of the few junglers that can do a early baron and he can rush dragon as good as shaco early.

Pros: Great initiator, Fast jungler, His W buffs attack speed for team, Good jungle control,great sustain, build tanky and still does damage.
Cons: Quicksilver sash counters his ulti, Most supports counter warwick's stun, weak ganks before 6, Doesn't match all team comps for his ganks.