Madred's Bloodrazor Tankwick is a great build on Warwick. He can soak a lot of damage (and usually won't get instagibbed as soon as he ults the enemy damage dealer) but deal respectable damage himself (20% max health Qs on a relatively short cooldown, MBR proccing at 1.6 attacks per second or so with W's steroid on, etc.). He's also pretty hard to take down.
Most of the time the build is something like (this isn't the order of the build):
Obviously this isn't set in stone, personally I'd just make Visage, Treads, and MBR core (possibly SF Cape too for health + armor) and everything else is situational.
Alternatively, you can also go Wit's End + Wriggle's Lantern Tankwick (it's about 100 gold cheaper but it makes you much more survivable as you get both Armor and MR instead of just Armor from MBR and your damage doesn't suffer too much iirc)
Later on you'll sell your Wriggle's for something else, obviously (as it's not a late game item). If you want, you can also turn this build back into MBR Tankwick if you're doing well as the game goes on (ie. Replace Wriggle's with MBR, replace Wit's End for another tank item).
Or... you can just go straight Wriggle's Tankwick.
Skill order is generally:
R > Q > W > E
But, after maxing Q, get Rank 3 Blood Scent and proceed to max W.
Oh. I also forgot to mention. After getting your Madred's Razors (not Bloodrazors), getting a Heart of Gold after then continuing whatever you want to do is great. You can choose to sell it or upgrade it to Randuin's Omen, which is another great item for Tankwick (and tanks in general too)