Though Warwick's strategy may vary from one summoner to another, he is an excellent jungler and a powerful solo laner.
Due to the sustain granted by Eternal Thirst and Hungering Strike, Warwick can easily remain at full health in the jungle, allowing him to take many jungle routes and making him difficult to counter-jungle.
In the jungle, Warwick benefits most from armor and attack speed runes as it increases the effectiveness of Eternal Thirst while making it easier to kill jungler monsters.
Hunter's Call can help a lot when pushing a lane since it will increase the attack speed of both you and your allies.
Turn Blood Scent off to fool weakened enemies into thinking that you are not nearby, but don't forget to turn it on again later.
Warwick excels at hunting down fleeing or weakened enemy champions after teamfights. At max level, Blood Scent reveals the location of enemy champs with less then 50% health from great distances and gives him a large boost in speed for chasing, it also reveals their locations for all friendly champs, making escapes very difficult while also preventing bush jukes.
Once Warwick hits level 6, his ganking ability becomes vastly greater as his Infinite Duress can almost ensure at least one enemy will die in a gank.
Warwick is also very useful in killing his pursuers. While running, cast Infinite Duress to regain most of the health you have lost, then spam the rest of your skills. This should shut down your pursuer's hope in killing you.
Take care when initiating a teamfight with Infinite Duress, as the enemy team will likely focus you quickly.
To maximize your ganking pressure you should try to force enemies to use their escape abilities such as Flash or Ghost before casting Infinite Duress.
When ganking, try saving Infinite Duress for later in the fight when enemies are trying to run away. This way you have a higher chance of getting a kill, however it is sometimes better to use Infinite Duress to suppress your target until your team catches up to them.
Only initiate the fight when your team can focus down an opponent to ensure they won't escape.
When choosing a target for Infinite Duress, be careful of targets who have spell-blocking abilities or Banshee's Veil, as it will completely negate the suppression on your ultimate.
Casting Infinite Duress on the enemy carry is the priority for Warwick in any team fight. The cooldown on the skill is relatively short, so don't be afraid to use it if you think it will grant your team a kill.
Due to the high damage and heal on Hungering Strike, Warwick works very well if you give him lots of resistance combined with spell penetration. While building him lots of on-hit effect effects like Wit's End and Malady is attractive, you risk making him a walking ultimate who will die very easily.
Blade of the Ruined King has a great synergy with his ultimate, but due to its high price and as most players choose to build tanky before going for damage, it is recommended that it should be bought as a fourth or maybe fifth item.
Remember that Infinite Duress cannot critical strike and does magic damage.
Building some survivability is crucial for Warwick since he has no innate defense mechanisms as a melee champion.
By building him tankier, Warwick becomes incredibly hard to kill due to high healing while still being able to put out hefty damage on enemies without having to fear sudden death. This will also maximize the effectiveness of any proc items you get by allowing him to stay in the fray for longer.
Warwick's lack of any multiple-target or AoE damage means he may miss out on assists during a team fight. Statikk Shiv ensures Warwick does some damage to nearby enemies when attacking, allowing for assist credit. Buffing friendly champions with Hunter's Call will also provide assist credit.
Warwick has the essential quality of any fighter, which is being both tanky and damage-capable. Therefore, a mix of items across tankiness, damage, and utility will maximize late game capacity on him.
Jungling order: Blue Golem (smite) → Wolves → Wraiths → Red Lizard (smite) → Small Golems → (Fountain / Gank) → Wolves → Wraiths → Small Golems → Wolves → Blue Golem → Wraiths → Red Lizard → (Gank) → Fountain at lv 7 → Dragon (assumes having Madred's Razors)
Note: Another set of starting items could be Cloth Armor, 2 × Health Potion, Sight Ward. The ward is almost always used to ward your own Blue Golem or Dragon, so if an enemy jungler attempts to take it, you can set up a gank. Alternatively, you can place the ward at enemy Blue/Red to try to gank the enemy champion trying to obtain the buff. Use Hunters Call after the 2nd attack in order to gain the most healing efficiency with Eternal Thirst.