1)  Pick a hero and a heroine
 If main character, the hero must have something against him.  He can either be an awkard peasent boy who’s really descended from some sort of royal or magical family, or he can be a member of the royal family who just doesn’t fit in.  Adventurous hero of might is preferable. See Arthur.
 If the main character is a heroine, she can come from a royal family or be a magical humaniod or magician.  She must be brave, strong, and corageous because it is illegal in these days to possibly have a major heroine who isn’t wonderful.  She should lack a few social graces, though, in order to endear her to her readers.  (ie, Aerin from The Hero and the Crown, or Crystal from the grove novels)

2)  Pick a villian. By no means give him logical reasons for what he (or, rarely, she) does.  Magician is always a proper profession, although power-hungry emperor is sometimes necessary.  Attractive is always a plus.  (ie, virtually all.  Orastagus from The Black Trillian, Sepharoph from Final Fantasy VII)

3)  Pick a fantasy world.  You can chose to have it magical, or not.  Be sure that it is faintly medieval, because no other times are worthy of note. Better put, make sure that it resembles Tennyson’s ideas on medievaldom.  Never make royalty bad.  If you have magic, you can either explain it in a scientific way, or just let it be.  (ie, The Belgariad, Black Trillian, well, just about all...)

4)  Populate your world with imaginary creatures, humanoid or no.  Make sure that these creatures are either from German or Greek mythology, as those are the only important mythos.  Also, you can make up your own, but this usually only works if they’re exactly like creatures from German or Greek mythology.  Various ideas.  From Greek:  centaurs, nymphs, hamadryads, nature gods, satyrs, etc.  From Norse:  gnomes, elves, trolls, dwarves  Mixing nationalities is fine.  (Favorite for this category: the Dragonlance novels which not only have large numbers of elves, gnomes, and dwarves, but also a few Greek creatures, like Minotaurs, and a few made up, like Irda and Kender.)

5)  Pick a few plot devices.  Favorites:
6)  Evil Emperor wants to take over the world (The Belgariad)
7)  Evil sorceror wants to take over the world (Wizard of the Grove, Hero and the Crown, etc.)
8)  Evil sorceror just wants to kill a lot of people, and/or enslave the world (Wizard of the Grove, Black Cauldron (Prydain) novels)
9)  Evil sorceror/emperor (works best with sorceror) wants to get with the heroine, can be main or secondary
10)  Note, if this one is chosen, how it is dealt with is imperative.  If the heroine is the main character, he will almost seduce her, but not quite manage to do this.  She will manage to escape at the last moment through some clever ploy and great strength of will of her own.  (Wizard of the Grove)
11)  If the heroine is secondary, again, the wizard won’t actually manage to seduce her, but he’ll probably be about to before the hero saves her.  This is often more of rape than seduction.  Also, in both cases, the wizard must be attractive.
12)  Characters must find all of some set in order to win, complete so many tasks, etc.  These tasks do not need to make sense with the plot.  The character may merely need to find all seven of some sacred object because when they are placed on a star the great god of good appears to save the day for no explicable reason.
13)  Female heroine has childhood love who, after completing quest, goes back to marry
14)  Male love falls in love with beautiful princess, can be childhood love, but doesn’t matter beyond being beautiful
15)  Comic side kick gets a few laughs
16)  Supernatural creature and/or wizard trains hero
17)  Sorceror or Emperor always stopped by some carefully planned action of the hero (never blind luck or a change of heart on the part of the sorceror)
18)  Evil sorceror casts some sort of illusion (or illusions) to fool heros
19)  Evil magicians always have black or red hair (exception, Riveda from The Fall of Atlantis, who was a blonde and Nakago from Fushigi Yugi who was also a blonde, but maybe he’s a warrior, so it doesn’t count.  But no matter what you do, do not let an evil magician have brown hair.  Brown hair is to evil like garlic to vampires, and no one knows why.)