Hello and welcome to my first guide. This guide is my take on how to effectively build and play Olaf in Dominion. Seeing as Dominion is new a lot in this guide is subject to change, this is just what I've found to be most effective at the moment.

For runes I pick up Greater Mark of Desolation for a little extra armor pen, Greater Seals of Alacrity for some extra attack speed, Greater Glyphs of Shielding for some magic resist, and Greater Quints of Swiftness because I want to go fast.

For masteries I go 21-8-1 picking up what ever I can in offense to boost my attacks, picking up some armor, magic resist, and dodge in the defense tree, and finally picking up improved Ghost and Exhaust. I currently have a utility tree build I'm testing out as well.

The items are pretty standard. Frozen Mallet is an Olaf staple. You can pick up merc treads but I find Berserkers Greaves to be a better choice for Dominion. I try to get a Giants Belt before Atma's depending on how hard the other team is hitting. Once you have your Atma's and Warmogs you can either build your Emblem and finish Yomuu's or finish your Stark's and then Yomuu's, depends on how bad you need that extra speed boost.

I max Reckless Swing first every time, then I finish Vicious Strikes, and finally Undertow. I max Undertow last because I only really want the slow, most of my damage comes from Reckless Swing and Vicious Strikes.

I use Ghost and Exhaust mainly.
Ghost is, in my opinion, one of the best summoner spells for Olaf and shouldn't be traded out. If you want to though you can switch out Exhaust for Garrison or Promote if you don't have one on your team yet.

I love playing Olaf, and I love playing Dominion. Olaf starts out slow but once you build him a bit he becomes a tide turner. I hope you like my build and I love feedback so if you have anything to add please comment!