Tactful ways to inform people that they're playing badly?

[Dreakon13]

As a relatively new player, two months in, I'll just say you can level up really quickly if you hit up the leveling roulette every day... and what I've played of the story so far, it's not very difficult/demanding. I'm a 50 DRG and a 40 PLD just from playing very casually by MMO standards.

I say this because I think it's pretty easy to get to level 50+ content and not know how to play your class optimally.

I personally try and soak in as much knowledge as I can but optimal ability rotations are still a pretty foreign concept to me (cooldowns in particular, attack combos are pretty straightfoward). I'm always open to advice so maybe I'm the exception and not the rule... but if someone came to me with a "how the hell did you get this far without knowing that" attitude, I may not be particularly receptive to that. Thankfully I haven't run into many unfriendly people and I've had some enlightening experiences running dungeons... but I'm also not too far in the MSQ yet so we'll see how higher level content goes lol.

...

Oh, and 99% of the guides you find floating around out there are horribly outdated. Even stuff from a year or two ago.