Hello there guys i want you to introduce you my way of playing Olaf . First of all i got two differnt ways of playing him here listed. The first one is about how i play him in a lane 5v5 and the second is about him jungling. Please remember that you do not ever play him like this so look at the Itemchapter where I explain what you should change against some enemys.

First of all I tell you why I took Greater Mark of Desolation . Armor Penetration is important for your physical damage. Greater Seal of Vitality is my second choice because it gives you more HP and Olafs Damage depends on his HP as soon as he got Atma's Impaler . You can also take Greater Seal of Armor but if you take Banshee's Veil and Force of Nature you got enough magic resist depending on what enemys you got. The Greater Glyph of Health gives you at the beginning much HP combined with Greater Seal of Vitality you got a HP advantage in the beginning which could lead to first blood depending on you. These two runes i took because they are in the early/mid game very devastating combined with Atma's Impaler and Tough It Out. The Greater Quintessence of Desolation adds some armor penetration to you so that you can do more melee damage.

The first masterie is 19/11/0. I went 19 in the Offensive Part because there you got Sunder which gives you 6Armor Penetration extra. I take Summoner's Wraith because it boosts both of your Summoners and makes you extra strong if you activate both of them. The defensive Part i mainly took because you got a bit survivability with Durability and Hardiness but essential for the early game Olaf is Veteran's Scars which boosts your HP and because of that your damage with Tough It Out and Atma's Impaler.
The jungle Olaf is 21/9/0. I took this way because of Executioner which could help you ganking lanes by boosting your damage. 3 Points in Vampirism helps you jungle a bit. The rest is like the lane Olaf.

I take aat the beginning Ruby Cristal because it gives you some health which could help you stay longer in a lane and this item is needed for Phage which you buy later. The next Items are Mercury's Treads which reduce the time you stay in a stun or slow/taunt or whatever so that you do not have to take your Ulti that often. The Frozen Mallet gives you Attack Damage, Health and slows your Opponent thats why it is ideal for Olaf because he aint the fastest Hero so that he can slows them if he dismissed with Undertow and it gives Tough It Out more effectniss. Warmog's Armor gives you very much Health thats why you take it quite early when you still fight in your lane so that your a nearly invincible. The next step is Atma's Impaler which grants you much damage relying on your runes and items you already got. The next Items can be chosen how you want. If you got many AP enemys you should firstly take Banshee's Veil and if this aint enough you can also take Force of Nature. If you got a well fed melee enemy like Tryndamere or whoever you can take Thornmail but remember only if he is well fed if he aint you waste your money. If you got a good tank like Amumu you can also take Bloodthirsterwhich heavily increases your damage so that you can kill the weakest enemy fast if Amumu stuns all of them but more of this later.

The lane Olaf beginns with Reckless Swing because it makes very heavy damage at the beginning combined with the slow of Undertow and your Reckless Swing and maybe someone ganking your lane you can take enemys in the early game very fast down and get your firstblood. Thats why you try to get Reckless Swing as fast as possible on Level 5.
Jungle Olaf is a bit differnt to this. He needs Tough It Out first because it grants him high Damage and Lifesteal boosts which is necessary if you want to jungle with him. Reckless Swing is skilled bit later because you do not need it at the beginning because you need your health and it costs to much or you have to use your Health Potion to early. But it is essential for your ganking because it gives you a big burst damage so that you should get it before your going to gank. After you got Ragnarok you should get Reckless Swing full because now you do not need more Life Steal but more burst damage for you ganks.

The lane Olaf got Exhaust because it can help you escape or you can help your jungler to get the gank in your lane. In addition Exhaust also reduces the Targets Armor and MR Summoner's Wraith. Ignite is very nice if you want to kill an enemy like Soraka or Nidalee or if someone with low heatlh escapes and you cast it on him so that he will die anyway. Also Ignite is good opening if you cast it one someone with Exhaust he got less armor and mr and you do more Damage because of Summoner's Wraith which increases your chance of winning the fight.
Jungle Olaf got Flash because Olaf is quite slow and if you want to gank someone you can intervene with this so that you surprise them and get your undertow on them. Smite is essential if you want to jungle because it gives you extra damage and makes jungle way more easy.

First of all both types of Olaf need many minion kills because there Items are very expensive. As lane Olaf you should try to last hit your minions as soon as possible but if you got an range enemy he will always hit you if you try that is why you should try to get the kills with Undertow if you loss to much mana you can buy yourself Mana Potion.
The Jungle Olaf starts at the Blue buff. You can ask someone for a pull but you do not need it but it makes you jungle faster. You start by using Smite on the Golem and killing him with Tough It Out. Then you go one with the little creeps as long as your Smite is not ready. Than you get the red buff just like the blue. Then you go back get your next Item and start ganking lanes. If there is no possibility look for creeps to kill and do not wait that will cost money and gives your enemys an advantage. When you sucessed ganking a lane stay there and kill all minions so that you can go without getting seen by any enemy because if the know that you go maybe to the blue buff they could try to make an ambush and the minions give you experience and money. Also remember that you play in a team ask your mates if you should take there lane because they have to go back to buy or something else. If you got no enemy jungler you can also go and kill there creeps.

You have to remember that Olaf is a team based character. You have to always look if your team is ready if it is not do not initiate because it is possibily that you die for nothing. Also ping your targets before you attack so that you team focuses one enemy so that you take one at first out. If you jungle write in the chat where you are going next to gank so that they can prepare. As the lane Olaf you should not push too much because it will make it way more difficult for your jungler to gank because the enemy are on the tower and the danger of getting ganked is way more increased if you are far away of your tower.

After all this explaining you should remember that Olaf is perfect only if you fight with your team. So talk to your team and do not flame someone for failing start helping him so that you increase his chance of getting better and you chance of getting more kills. So far hope you enjoy my guide.