I bought Irelia a good time ago, but I do pretty bad with her. It's not like I feed or anything like someone press tab and see a 1/8/1 score... But I see soo many posts that say that she's one of the bests champs and etc. So, Is it worth to master her? If it is, any guides/tips/anything?

Yes she is good

But it takes some skill to play her, and even harder to master her.

So I should invest on her?

Well if you've seen Pro Irelia player, and you like that
You should invest in that, she's kinda considered a hyper carry in which if you do real good in a game you can carry almost any game

too be good with her now you have get lucky in who you lane against and farm harder than most other tops

she needs at least triforce wits and randuins to be amazing, and with her nerfs her laning got weaker and with how weak she is pre6 you can get bullied out easily by most tops

She's been nerfed out of viability currently.

She's NEVER been considered a hyper carry in ANY capacity. Sorry Ricky, you're bad at Irelia.

When they buff her again she'll probably be okay again, but atm she's kind of underpowered and probably not worth learning.

On the flipside, if you can learn to survive and do decently with her now, you'll tear up the competition when she's brought back up to speed. Survival in the face of adversity and all that.

Irelia is still viable. It's just that a number of the guides on her are out of date and when people follow them to the letter, they do not end up doing so well.

Some general tips on Irelia are:

• Irelia needs to farm a fair bit in order to complete her build. So you will need to last hit very reliably in early game. If you are being denied or harassed, switching to gold items can help.

• Irelia excels in mid-game where the true damage of her W shines, try to utilise this part of the game to gain an advantage for your team. Do not always activate W when you want to engage, since it tips off the other side that you are going to attack.

• W is also the reason that Irelia can get away with being tanky.

• Irelia’s R has a friendly CD and should be used liberally, rather than conservatively.

• Irelia should not usually initiate fights, because in team fights, her priority targets are the carries.

• Irelia’s passive can sometimes be used to detect impending gank or hidden characters, but it is not so reliable.

Hope these help.

Thank you all for the tips... I'll try her now!