When you start the game on 3 v 3 buy boots and 2 health poitions and 1 mana just in case. when you do all that battling be sure to have enough money to buy Berserker's Greaves right away. If you dont then buy the boots of speed. Harass with the Axe and if your close enough Use your turn on your W then shoot your axe and use your E, then keep on hitting for a powerful combo.

(Items you should have in this range: Berseker's Greaves, Maybe Atma's if they fed you or a bit of Atma's Ampaler)

Once your in that range of the level, get red buffs and get at least 5 kills to be a powerful Olaf when you advance farther, don't always but getting the red buff is great, and so is getting the dragon. Get lots of money for more items and items = more power. If you have a carry give them some kills but, you would still want to get some kills. you should be doing good by now or great.

(Item's you should have in this range: Berserker's Greaves, Atma's Ampaler, and proboaly parts of the Frozen Malet.)

Once your 18 and you have the items you should be doing amazing, tanky and Powerful. Remember get the red buff, also the dragon. Then get lots of kills or assists and dont die over 10 then i would think you will be losing :/ But beasting for the team. Also i think you would have won without getting to 18 yet...

(Items you should have in this range: Berserker's Greaves, Atma's Ampaler Frozen Malet, Maybe parts of your second or 1st Warmog's but get atleast 1 Warmog's Armour.)

Everything else should be fine. Also this is my first build i made, also there is Thornmail's and Spirit Vasage at the end, it depends if there doing magic damage or attack damage

Attack Damage = Thornmail's

Magic Damage = Spirit Vasage