Greybeard
Minstrel
What are the most overused fantasy cliches? And must these cliches necessarily be avoided?
About the only thing I would consider cliche would be the whole "child of prophecy" thing, or the standard Luke Skywalker set-up: kid from a rural town is surprisingly adept when it comes to magic, swordplay, etc. and loses his adopted parents/guardians, then embarks on a quest of epic proportions with a Wise Old Person to right the wrongs of the world with the help of a band of rag-tag adventurers (namely, a princess in disguise, a thief/smuggler/prostitute with a heart of gold, and a perky/annoying sidekick). The villain may or may not turn out to be the hero's long-lost father/uncle/second-cousin's-best friend's-former roomate.
I'm sure there are other story set-ups that have been used to death, but this is the main one that springs to mind. I don't think there's anything wrong with using such a set-up, just be aware that some readers might look at it and say, "What, this again?"
Which begs the question....how much of an original idea can we, as writers, have anymore?
That isn't to say that one shouldn't at least attempt to bring something new to the table, whether it's a spin on a classic trope or a new magic system, etc. just to keep things fresh. But I think it's an unrealistic goal to be 100% original. Most everything has been written already. It's our job, now, to take what we know and add our own flavor to it.
Cliches I really hate are the prophecy that already determines how the story ends. That was one of the things that spoiled Harry Potter for me. I would really have preferred to have Harry act du to his own free will and not because he's supposed to be the only one able to do so because of some prophecy. The same goes for any other story.
But in most stories - the prophecies are self-fulfilled. Even Dumbledore pointed out - had no one ever overheard Trewlaney would Voldemort have ever attacked Harry or his parents? Probably - because he was an evil man - but he specifically went after them because of the prophecy.