This will be a guide to a tanky yet powerful olaf.

These runes will provide olaf with high hp in the beginning of the game gaining him the advantage when 1v1 fights.

The items help him stay alive and yet deal damage so he doesn't depends on his true damage.

Pros :
Tanky
Good amount of damage
Can chase easily
Cons :
Not as tanky that he can truly be.
Not easy to escape (Dont need to escape if you win)

If you want to jungle change ignite to smite and follow with this build. Have a hard leash and a leash on red.

Haha. Not sure if it is teamwork but it is very easy to killsteal. It is easy to 1v1 or even 1v2. In team fights you can usually pick up a double ill or even triple or more.