Not Updated For Current Season
This build has seemed to work for me.
Early game no hard harassing unless you have a good support with you like Janna or Morgana.
Exhast- Always good for 1v1 fights, and also nice for ganks/chase.
Ghost- Catching champs with Frozen Mallet helps alot, but if you can't get that
hit in it kind of goes to waste. Aslo helps avoiding Ganks.
I start with with berserk boots so you can catch those low early and help avoid getting ganked.
The frozen Mallet is obvious for any Olaf because it provides nice help for his Vicious Strikes and keeps them slowed and in range of Reckless Swing.
The game is usually over after I can get Madred's Bloodrazor. Deals nice magic damage to tank and with his passive getting his 25 hits times 4% is fast.
If the game hasn't ended yet, a good choice would either be the BloodTherster or the Millady.