Hello guys i'm unranked curently, but i'm a very good irelia main and i have played her since season 3, back when i was gold 3. I restarted playing league since 2014 x-mas and my first champ bought was irelia. When i play with her i beat plats and even diamonds( i checked ),so i figured to make a guide.Oh and im not english so there can be many mistakes ^^ . this is my very first guide so please understand ^^

Irelia's early game isn't that bad,you have to try to farm as much as you can. When you get the sheen you can go start trading much better.You have to try to get you're sheen when you get level 6- this is you're early power-spike.I usually kill my laner at level 6-7. When you get you're trinity force try to roam becouse at this point ( if youre not behind) you can duel anyone. Oh and dont stay in you're lane forever like nasus, becouse you are a tanky assasin who can kill anyone so in teamfight's you will be needed. In the 50min-1h mark you will start to fall off so make sure you do what you can before that.

Pros:

Nice sustain
High Burst with sheen
Great Tenacity
Can take jungle camp level 1
good snowball
has gap-closer
good CC
stiky

Cons:

must dive
everyone will focus you
can't 1v5
need items

When you have trinity force and you were maxing W you can activate it and Q to a backline minion to get the reset.
Later in game you can use you're R on minions to catch-up to the enemy ( for more experienced players)
You're R doesn't interrupt you're AA
Try to KS kills with you're W+Q :)

In ranked always take wolves level 1 and take W. Take TP aswell. Unless you're against swain then take ignite and don't do wolves.