Irelia is a reliable champion for SoloQ or Competitive play. She can be a tank or an assassin for whatever reasons. Lane phase may be a little rough for you but if you make it to late game you will be a monster. Playing mid/late game you want to be either a split pushing tank or a CC bot in a teamfight.

Starting W on irelia is a good choice most of the time and it should be what you max first. The true damage on her W goes up 15 Per rank and the heal also good for sustaining in lane. Getting Q or E on her at level two is your choice. Level 3 you should have all of her abilities every time.

Flash and Ignite are the basic spells for top lane but if you think you are going to have a hard time for reasons Heal or Cleanse are also good but always take flash.

Pros
She is a solid champ for everybody
True damage is good against tanks
2 second stun!
A complete badass
Cons
Can be set really far back if camped
High skill cap ( need high mechanics to be played at full potential)
Attack speed reduction affects her really hard

Jumping on the enemy teams carrys are what you should do in a teamfight or pushing a lane as a team if a fight breaks out. Try to stun the enemy Marksman and then go to the Mage because making the enemy marksman not damage anything for 2 seconds is pretty strong, While also damaging the enemy mage at the same time is absurd.

This should be pretty easy with her after level 5 or so. A basic attack with W on with Q should kill the minions but you can run out of mana quickly doing this too much. Its pretty simple with her.

She is a very solid pick for anybody. Being an uncommon champion is good because most of the games you play you can get her. She is fun and strong so why not play her.

P.S I put alot of effort into this guide so would enjoy if you would rate this and leave a comment so i can improve and make more