First and foremost with this build never stop farming. Until you reach full build your priority should be getting to full build, without letting your lanes get too trashed if it can be helped. Your goal with this build is to pick up kills where you can after clearing your jungle, maintain control over dragon and herald, stealing camps from the enemy jungle when you can, and then ultimately popping off late game as an unkillable war machine crawling out of jungle hell with a penchant for unrefined and limitless violence in your opponent's general direction.

This part can be easy, or tricky depending on your team and the enemy jungler. It will be suggested that in most cases you anticipate which camp the enemy jungler will start at, and take up your camp on the same side of the map. After that kill gromp, go for the buff you haven't collected yet and go pick up a free kill on the enemy jungler at the buff you expect them to be at. If they haven't taken the buff but aren't there, ward that camp's bush, go for one of their nearby camps and/or scuttle and be ready to beat them down when they show up. If you expect that you will be unable to kill the enemy jungler for any reason, it may still be worth it to smite their buff from hiding and then go back to farming your own jungle.

After your first reset you should be able to at least buy Stalker's Blade or tiamat, if you managed a kill or farmed a little longer. In either case you are able to take dragon solo. Check for wards and take care of it yourself, or gank a lane and try to get your team to assist you. You can prepare to take Herald after this point.

Early on focus on getting tiamat if you want to farm more quickly, or Stalker's Blade if you expect to be ganking more frequently. Between the slow on your undertow, chilling smite, and the speed boost from Approach Velocity you should have no problem keeping on top of most enemy laners.

After completing both Stalker's Blade and Tiamat you want to make a decision on your next item based on what you're doing more. If you are farming or ganking the enemy jungler then Ravenous Hydra is likely the best next item. Alternatively if you are spending more time helping lanes then Frozen mallet is easily a better choice. You will slow enemies, have no time keeping on top of them even if they flash away, and be able to take more punishment in general. At this point in the game you want to focus getting both items and an Aegis when convenient to transition into the late game with a solid balance of damage, self healing, and defense.

If you keep farming at all stages up to this point, or rack up numerous kills, you should be well on your way to the next two items that make Olaf go from a hardy nuisance to an inescapable terror. The new Death's Dance in tandem with Spirit Visage will lead you to a point of nigh immortality. Look for opportunities to rush in and focus on damage dealers, only activate your ult when you get CC'd during initiation or when you are on top of your target, and watch as the enemy team struggles to stick any damage to you as you melt through their biggest threats.