When writing a fantasy story, remember that modern technology cannot possibly exist. There are no computers, phones, cars or electricity whatsoever.
Everyone keeps in touch by handwritten letter's sent by carrier pigeon, or owl, and they must all operate by candle light and wood stoves, heating is non-existent and everyone walks EVERYWHERE. Don't mind that there are horses and your main character's could easily rent some, and/or are expert thieves and have no qualms with stealing some, they must walk on their epic journey, otherwise, they've cheated.
Despite being dirt poor, all character's must own at least one book, even though your fantasy world is based on a time when only rich people could afford books, and/or even knew how to read. *coughMedeviltimescough*
Schools also do not exist in the modernized form, and only serve to teach your character how to be a BAdAsS*, who can kill twenty people all at once with their little finger. This place also serves to introduce the childhood best friend of MC/rival/love interest who will eventually fall in love with them at some point and should definitely die for this.
People also always eat noodles of some sort (aka: Ramen) with chopsticks, despite the fact that these are of Asian origin and everyone in that time ate with their hands, even the king.
Also, on your character's journey, there should always be a conveniently placed apple tree, or berry bush, or growth of mysterious edible mushrooms. Other sorts of trees like pear, orange, or pineapple don't exist, nor do grape vines or vegetables. Those things must be grown in people's garden's, because of course, that's where they originated after all. Ra forbid their be natural vegetables in the world. . .
*wHEn wRiTInG bE SuRe 2 tYPe lYKe tHz, rEaDErS <3 EEEEET.