Feel free to stop by and chat. Looking to improve and I hope to see you on the Rift! Breaking my Platinum Shackles this season.

Olaf is a GREAT BLIND PICK at the moment. He can farm quickly, conqueror is in a great spot right now, and finally he has a decent gank and chase potential against champions that try to use slows or stuns to kite (aka Ashe)

Olaf has the opportunity to build in two distinct ways.
He can chase down anything or get into the thick of things and really fight it out.

This is game dependent but SMITE matters-
CHASE/BLUE SMITE OLAF
If you need to get to the backline and they have high mobility, chase olaf is the way to go. Examples of this are against Ezreal, Lucian, and other characters with multiple dashes that need to be taken out.
Beginner Note: Pick blue when you start running Olaf to help you land axes. It is a reliable slow. This gives you the added goal to move to red smite once you have the hang of him.

DUEL/RED SMITE OLAF
In most instances, red smite is better. The burn on red smite combined with your W, black cleaver, and conqueror gives you massive damage. Oftentimes this will just do more for you.

Deviating from Core Items
When you are ahead- you can really choose whatever keeps your opponents down. If you are playing Solo Q like me- every person on your team is a carry. Assassin carry, adc, velkox support carry, you name it they are trying to carry. I like to take my leads and secure early hexdrinkers, or other defensive stats to keep me in the thick of things and let my carry squad carry. Play against your enemy team- think what would make them die more.
Early stopwatches can be clutch- even if you decide not to get GA.
Having trouble catching them or need that prime shutown? Get a righteous glory. With Warrior enchant alone you can kill them.

You have NO need for.You just do not need these. Unless their entire team picks mages- just dont waste the money. Get an early if you need the MR or a Hexdrinker if they are burst mages.

Other Bad Items:
- Black Cleaver is better
- just no
- Death's dance is better
- too expensive for how fast you farm already.

There are so many paths to take in S10 it is fantastic.
Let us focus on what you want to do:

Getting a Leash:
If you opt for a leash (which is fine), it places you sometimes on the side of the map you do not want to be. Ganking top has lower value unlesss it is a volatile match-up. Example Riven v. Fiora or Darius v. Renekton. One kill can swing the entire lane in these fights.
Blue Side: Red, Krug, Raptors, Wolves, Blue, Scuttle-> Gank Top or Reset
Red Side: Blue, wolves, raptors, Red-> Gank Top or Krugs -> Scuttle & Reset

No Leash- Planning your path (Ganking Bot Lane)
Blue Side: Raptors, Red, Wolves, Blue-> Gank Bot or Gromp-> Scuttle. Note: Look to take Raptors if they are a jungler who does not excel and their are no gank opportunities. A deep ward here helps.
Red Side: Blue, wolves, raptors, Red-> Gank Bot or Krugs -> Scuttle & Reset

You start up your game- get invaded and 4 of your teammates die, when you finally get back to your buff its gone. What do you do?
No worries- Olaf is SO GOOD right now you can still win this.
You need to farm now, hard. For warrior enchant to boots to black cleaver. Always get cleaver first if you are behind. You want to take fights again once the warrior enchant is done (stall and concede a single dragon if needed to get to this point).
just q everything and farm quickly. You can full clear your jungle in a little over 3 minutes with Olaf.
Play on jungle resets and pressure lanes if you have no camps up. Just you hitting a laner with an axe can make all the difference if they have no pots or sustain.

IMPORTANTLY: you want to track the enemy jungler- countergank if possible- and farm until you reach the powerspikes below.

You have three major power spikes.
[*]- this gives you the AD of a BF sword. It gives you all the damage you need.
[*] - shred everything. Three hits and every champs base armor is basically halved.
[*] - You have never really healed until you healed with this. This is where you see Olafs kill 3 people with 5-15% life.

Dragons are important but if you are behind- dont worry. Only the dragons from 3+ are VITAL.
Farm to your next item and try to turn the fight with sheer stats alone.
Late game you need to be more deliberate with your ults and who are you are going to kill. If your team is killing the backline, peel for your ADC. If their backline is killing you. Whelp you may have to go beserk and die for their sins. You can easily get a kill before you die. Target their damage source and pop that ult.

Could add more here- but it is getting late. Let me know what your are struggling with. I am happy to help those in need improve.
Olaf can break any elo- he has great versatility and carry potentially. Revert to farming when behind.
This is my first guide and feedback is appreciated.