Not Updated For Current Season
Olaf is a melee champion with a lot of health. Though a lot of people mistake him for a tank, he's really just a dps champion with good survivability. With this build, you get a rediculous amount of life steal and you'll quickly get rediculous attack speed the lower your health. Since you have so much life steal, you'll quickly recover from being targetted or barely feel the damage at all. For the item choices, they rotate around some key elements for Olaf: Lifesteal, Dodge and then Health.
With Olaf, the more health you have the more damage you do with Vicious Strikes, and the more Life Steal you have the more HP you heal with Vicious Strikes and with stand alone damage. Only one of Olafs abilities scale with attack damage, therefore, it's not the highest priority.
Greater Mark of Fortitude x9: I chose these Marks because your initial health is where it hurts, you don't get health until later if you stick with my item order and it's just useful. Honestly, this beats out the per level runes since you need the health ASAP not later.
Greater Mark of Desolation x9: These are useful since you have a passive ArP boost from your Ragnarok, and honestly, stacking up that ArP isn't a bad second Choice.
Greater Mark of Vitality x9: Once again, it's more of preference based. I chose the other ones because you get more health sooner then later. If you feel that the bit of health difference is crutial, then go for it.
Greater Seal of Evasion: I chose this because I enjoy the extra chance to dodge, every little bit helps when you're confronting a melee hero, or anyone honestly.
Greater Seal of Fortitude: Better initial life, just like the marks. Between this and the Evasion Seal, it definately is a preference.
Greater Seal of Vitality: ^ but later health, not as much initial
Greater Glyph of Focus: Cooldown reduction. You use stuff sooner, is about as much as I care to say.
Greater Glyph of Celerity: More Cooldown reduction at 18. Earlier of Later cooldowns up to you.
Greater Quintessence of Fortitude: More Health, as Olaf this is awesome. I can't imagine any other Quint for these spots.
but because you asked:
Greater Quintessence of Vitality: More health, but at 18
Greater Quintessence of Desolation: If you want just large amount of ArP without having to worry about items.
Do not Replace:
Flash: Crazy overpowered. It allows you to teleport through walls, away from towers, into enemies faces. Just amazing. I prefer this one over ghost because with Olaf, you have no jump to the enemy so once they see you coming they can prepare themselves by ducking around a tower or moving to friends. Although it doesn't have the awesome chasing abilities like Ghost, this has, in my opinion, beter escapability then Ghost. Plus it's pretty damn fun to port infront of someone and reckless swing their face off.
Exhaust: A useful skill, with the mastery boost it has an increased duration and armor/spell resist reduction. It also slows, which is useful. Ontop of the slow is the 100% blind (or at least it says 100%) which will stop melee enemies from hitting you, great for melee enemies that you don't think you can take down before they kill you.
Ghost: More chase / escape if you can't manage with just Flash. Also a great replacement for low levels if you haven't quite gotten Flash yet.
Smite: If you're some kinda wierd jungling Olaf, then take it and switch the exhaust mastery with this ones mastery. Then hit the jungle (I'd advise maxing Vicious Strikes first)
Ignite: IF you think you honestly need the little dot, then go for it.
Clarity: If you really think you'll use that much mana, or are having mana issues, or have a mean person you're in vent with who's all like "Grab Clarity I need it. Then go for it, otherwise screw it!
Rally: Go away.
Teleport: If you have troubles or go 'b' too much then go for this, it's pretty useful to get back and forth.
Heal: Meh, if you want it. I personally don't like heal, it implies that you're planning on losing health. A real pro plans to never lose health hur hur hur......but I guess that would kinda make Olaf useless eh....ah well
Cleanse: Well, you have your ult which is a cleanse on steroids. If you think that you need to remove the CCs that much from 1-6 and that you can't wait for your ult to be off cooldown, go for it, but I'd advise against it.
Clairvoyance: Short cooldown, you can see if you can run into those bushes to kill someone or if you'd get ganked. But other skills are better served with Olaf. (i.e get someone else to do it)
Fortify: Well, if you think that it's necessary to have it and have the option then get it. I personally think that if your team is any good you won't need this.
Revive: ....no, never, ever, EVER EVER EVER................EVER
Skill Choices per level:
Under Toe: Levels: 1, 14, 15, 17, 18
My Summary: Slows when you hit. Decent range, goes through stuff. Not that much damage, but slows. Small range, easy to miss. But it Slows. You can also pick up your axe after you throw it and get the cooldown reduced by 6 seconds off of like a 9 second cooldown.
What you should use this for: It slows, you use it to slow people. OR hit people when they're far away from you, maybe get a kill.
Why first point?: Because it's slow is useful, Olaf has absolutely no CC, no range moves. Except this one, and it SLOWS (that's right it slows is the thing you should take away from this.) Its incredibly useful for ganking since if you hit multiple people it will slow ALL of them.
Why not max first?: As for why you wait to level this later. Like I said earlier in this thing, you don't get much attack damage with this build, and guess what, this is the one ability that gets more damage based on attack damage. So the initial level is fine because the starting slow is a whopping 24%. Plus it has a short cooldown already, no need to get it higher to reduce the cooldown.
Vicious Strikes: Levels: 3, 8, 10, 12, 13
My Summary: Awesome.
What it actually does: Gives you increased damage based on your total health. Gives you life steal when it activates. Like I said, awesome.
What you should use this for: Everything, when ever you're fighting someone use it when it's up.
Why not max first?: As crantastic as this skill is, the burst part of your damage doesn't come from this skill. Just the sustained damage. With Olaf your burst is much more effective early game. Though this ability is a close second. And if you prefer the melee aspect of the combat over the burst, then I'd say max this first.
Reckless Swing: Levels: 2, 4, 5, 7, 9
My Summary: Boom!
What it actually does: Deals [true]damage to a single target. Then deals some damage to you.
True damage?: Now, I'm not 100% sure, and if I'm wrong, leave a comment and I'll change this. But True damage is damage that isn't effected by Defense or Magic Resist. Now matter how much they have this skill will always deal X damage. And it hurts.
Why max first?: Because this is where the bulk of your damage will come from at the start. Early games are all about the burst and hell, this guys got it. The sooner this is max the sooner you'll be steam rolling through buggers down the lane.
THIS SKILL: It's your ultimate, whenever you can level it up do it.
What it does:
Passive: Gives your ArP
Active: Gives you immunity to CC, and gives you a sexy bit of damage reduction.
How to start and finish a fight:
Do not initiate! In a team fight this is crutial. Although you have health, people cut through Olaf with little to no problem. Run in second, or third. Then make sure you don't get separated from the team, because if you do, you're gonna get burned down.
Watch your health! When you're one on oneing with someone, make sure you think about if they can kill you. If their nuke will one shot you doesn't matter how much Life Steal you have, they'll blow your face off.
Take note of your positioning! If your allies are on the other side of the map and you're on your own, chances are they're not gonna make it to you, hug that tower. And if there's 5 of them, and you know they can get you, run your butt back to base or your team.
Don't be baited! Trust me, if they're a good distance ahead of you, you're not gonna make it. Next thing you know there's 5 guys up in yo' face messing you up. If there's just one guy then go after them, if they start dancing around the turret and you see your health dropping, probably means it's a good time to get out.
Low Health? After an exhausting team fight, and you're looking a little ragged. Head to the jungle, you've got enough life steal to heal yourself up. But, if there's multiple enemies up and some of them just disappeared from your view, now would be a good time to find a safe bush and hit 'b'. If there's no time, do the good old fashioned thing and run back to base, trust me a dead Olaf is a useless Olaf.