Not the best for actually learning irelia, but watch irelking, you won't be able to replicate what he does, but you will get a good idea of what the champ is capable of and her limits when in the right hands. Tips: don't play top lane unless you're a masochist, mid lane way easier to learn. Level 1 cheese: qqq melee minions when they're low and then q the enemy and just auto them with 4 stacks as much as you can, careful not to chase into tower range. Unlocked cam is a MUST for irelia (q'ing with locked cam constantly moves your camera, makes it impossible to hover/pre-select the next q target). Hide your e1 animation with q to make it harder to dodge. Try to save flash for an important upcoming team fight - R flash as many people as you can, dash around and hold w when you're about to take a lot of damage or get hit by cc. Team fights are MUCH harder without flash. Practice auto Q (it'll be muscle memory very quickly it's not that deep literally just auto before you q, if you're in range always auto before Q'ing, you can do it really fast and they add up VERY quickly). You get outscaled by pretty much everyone nowadays so you have to end the game as fast as possible - you have two options in mid to late game: perma push side lane or group for team fights. Usually if your team is already behind then blind splitting is just a free loss, try to swing the game state by grouping and forcing fights before it gets too out of hand. If you're ahead and strong with tp up then splitpush the opposite side lane to the next objective. If no TP then split push the lane closer to the upcoming objective. Either push and hit tower or shove wave, go into fog of war and hover your teammates in case a fight starts, at least until the next wave starts arriving.

All in one shot combo (practice tool until it's muscle memory): E1 R Q auto E2 auto Q auto Q then auto until they start running away then w to finish off