Yeah.... It varies, depending on what mood I'm in.
I'm less likely to be looking for:
1.) The classic Tolkienite type of fantasy, with stereotypical elves, dwarves and orchs, and with the conflict clearly defined into black and white, good vs evil. Not because good vs evil can't be interesting, but because it's difficult to make interesting, and a lot of people fail. Also, I've read a metric ton of it, and want to see something new.
2.) The whole prophesied hero/orphan farmboy is really a king trope. It's also been done, and there's very little tension or interest in it these days, because there's only really two ways for it to end - either the prophesied hero/orphan farmboy does really well in their new role, or they don't.
3.) Deus ex magica. If the central conflict, or whatever pinch your characters is in, can be solved by hand waving and a bit of magic, that's a bit boring.
I'm more likely to be looking for:
1.) Inventive use of magic. Don't just give me white-bearded wizards with robes and staffs (with all due respect to Gandalf); give me something new and interesting! Is your magic dependent on language, and new spells crafted with new words, or combinations of words? Is it tied to the landscape in which it is cast - with magic dust-storms in deserts, or magic tsunamis along shorelines? Is it dependent on the caster's life-energy, or do they have to go through some elaborate spiritual ritual to become mages? Tinker with this, and try to make something new and inventive and well thought out.
2.) Imaginative world-building. If your fantasy world is just "medieval Europe but with elves and dragons", I'm probably going to be sceptical. You've got all the freedom you want to do absolutely anthing. Give me some islands floating in the air, or mountains made of crystals, or giant titanic beasts chained under the ground and guarded by immortal watchers - give me archipelagos that move, or deserts made of blue sand, or whatever. You've got the power - use it.
3.) A sense of adventure and wonder. This is a brand new world you've playing with, yes - but the story is not a travelogue. Give me characters who are going somewhere, with good reasons for going. Give me exploration, discovery, tension and high stakes. Or, if your story is set in one place, and is more of a fantasy-themed slice-of-life, get me invested in the characters and the world around them, and make me care. So your character is a magical cobbler, and not a magical adventurer - why is that cool and interesting?