Not Updated For Current Season
This is my first build, and any creative criticism is accepted.
Pick up a Dagger and a Health Potion. (I haven't mid with irelia yet, so i don't know how my build would work in that situation.)
Select Hiten Style for your first ability so lifesteal will keep you in your lane.
Irelia is not a very good tank killer until later in the game. So play it safe until you feel you are ready to take down a heavily built tank like alistar or rammus.
Just farm minions and once you reach level 2, throw a point in Bladesurge and tease with that. (careful, don't get yourself in a situation you won't be able to escape from!)
Once you are level 6, it's time to shine. Throw a point on your ult and if the opportunity arises. Bladesurge into battle, Hiten Style, Equilibrium Strike, and then Ult it up. Your ult can travel a pretty long distance, so if you feel you can hit that weakened twisted fate hiding behind his turret with your ult, by all means!
After you have rampaged your lane and destroyed your turret, and by now you should be close to buying Madred's Bloodrazor. Head to other lanes and gank them. If you ever find yourself wandering around in the jungle, feel free to pick up lizard and golem buff.
Alright, this is where my build becomes somewhat fuzzy, because every single game i've played with her, they end up surrendering.
Now if you feel like you are having a problem in the game (IE: You are too slow, too weak, not much health, no armor, or whatever problem you have) just change the build up a bit.
TOO SLOW: Get Phantom Dancer
TOO WEAK: Bloodthirster or Infinity Edge
NOT MUCH HEALTH: Frozen Mallet
NO ARMOR: Randuins Omen
Well, that's just about it. This build is just more or less kind of a guide on items and playstyle, but other than that, it is a very flexible build. Please tell me how i can improve my build, it would be much appreciated!