This list of Young Adult novel tropes and clichés first appeared in my parody novel Dire Virgins. This is why you will find references here to names of characters appearing in that parody, such as eLess, Mox, Tatu, Toby-Ass, Tokina, and so on.
Your main character must be a female, typically fourteen to seventeen years old. My main character, eLess is perfectly in the sweet spot here as indeed are pretty much all of the successful Hunger Games rip-off novels.
The Main Female Character (MFC) must be homely and plain in appearance, but not outright ugly, and she must know this about herself only too well. eLess knows this intimately about herself as do most MFCs in nearly all YA trilogies and series.
Nomenclature (part one)
The MFC must have a long, if not outright spectacular name, but the name must be shortened to something cheap and nasty to infantilize her. Hence eLess: the perfectly-demeaning name. Note that if your MFC or her parents (if in existence - see Parental Units, below) fails to shorten it, one of the inevitable two guys (see Inevitable Triangle, below) must shorten it for her, or give her a demeaning pet name. 'Stiffie' is a good demeaning name and has the advantage of being rife with double-entendre.
The MFC pretty much has to be a loner, virtually, if not actually, hence eLess, although surrounded by members of her fiction in this novel, is the only one (so she initially believes) from Abjection, and she's the smallest, which both isolates her and contributes strongly to the necessary infantilization and marginalization of your main female characters.
The MFC has to have extraordinary issues - that is, she must have mental problems which aren't normal for a child her age. eLess, for example, is haunted by her betrayal of Abjection.
The MFC must arrive at a new faction/group/school/town/tribe. This facilitates her both being a loner, and being 'special'.
The MFC has, or soon ends up with, a quirky side-kick (who I tend to like far more than the main character!). In eLess's case, this is Tokina, the token black girl (see Tokenism, below)
At least one parent, preferably both, is not in the picture. The best way to do this is to have them killed off tragically, or stupidly, as I do with both eLess's parental units.
This isn't really critical, but it can add a certain poignancy to your fiction, especially if you kill off the older influence. So your character might be unusually close to an older relative such as a grandmother. In eLess's case, the older influence is Tatu who gets killed off, which is sad, but only because she's the only Asian in the entire novel.
Betrayal of your MFC
Yes, your MFC must be betrayed in the novel, but it's also very effective to completely undermine your novel by creating a purportedly strong main female character, and then undermining your work by depicting all other female characters in traditional gender rôles as though it's the 1950's.
The MFC's father cannot ever be the biggest male influence in her life. That's a huge mistake, because we know that this never happens in real life. No, your MFC must have at least one, preferably two, preferably slightly older guys who can completely overshadow and very effectively replace the father figure. The guys must be hot and if she's going to have two, they must be polar opposites who immediately show an unnatural interest in her and quickly become the controlling power in her so-called life; never underestimate the importance of this. Your MFC cannot, I repeat absolutely cannot be allowed to take charge of her own life or even have a life outside of the pernicious influence of at least one guy. This is critical. Never forget that she's not a woman but a girl and therefore must be controlled by a guy at all times. eLess, as you know, is entirely under the power of Toby-Ass aka 10:4 and it's just a wall that she is.
Age of Male Influence
The guy is typically the same age, but preferably somewhat older in order to become her symbolic (if not with some bollocks) father as well as her lover. Why is that wrong?
Even societies in the most chronologically distant fantasies have electricity. It's between the MFC and at least one guy whenever they touch. It's shocking, I know, but you cannot forget this, otherwise you risk your MFC operating on her own and that would never do. You must amp it up by having your MFC recharged at regular intervals. It's currently how these trope MFCs are controlled, rather like the dinosaurs in Jurassic Park are controlled by withholding an enzyme. Your MFC cannot truly have any power; YA insists that women aren't wired that way.
At least one of the guys must be brooding (no word on when the eggs will hatch) and secretive, preferably both.
The MFC must see the guy without his shirt on, and quite soon after she meets him. If you can have him stripped down when she meets him, this would be perfect. Why? Read on....
The guy is muscular
In stripping the guy, the young, impressionable, female readers get to see his 'chiseled abs'. 'Chiseled abs' are critical because you know that no guy who lacks them is of any value whatsoever. In fact, such sickly and worthless guys need to be exterminated ASAP. The Nazi's had it right with their ideas of Aryan perfection, which you will see running rampant in all YA fiction rip-off trilogies. Also, if you can actually use the word 'chiseled', do so.
Hate = Love
The girl and the guy hate each other on sight but this 'hatred' is really just another word for instadore. Some people employ the term 'insta-love', but it's not actually love, so my phrase is much better. Note that this is in full compliance with the long established principle that guys have been taught to employ, which is that 'No' and 'Yes' are interchangeable, and can actually mean the same thing, especially when said by a girl. There is no such thing as rape in a YA trilogy, so feel free to have at it, as indeed should all your male characters, and especially if they're 'dumb jocks' because no jock can be smart, and no girl can be a jock!
The guy is troubled
At least one of your YA guys must be deeply troubled over something (which can, in the end, be completely trivial), but only your special girl can wheedle out what this trouble is.
n Each Other's Arms
Your MFC must end up in at least one of your guy's arms because of some ridiculous happenstance which literally throws them together. The train rides in Dire Virgins are the engines of this locomotion, and accomplish it admirably and keep things on track.
The Weak Girl is Injured
No matter how special your MFC is, she must be injured to show how tough she is - because toughness only equates with physical injury - never anything else. Once you have her injured, you can immediately negate this purported toughness by having your guy rescue her and nurse her to health. The guy must take care of her even when a parent (if in existence), or her bestie, or even competent and willing medical personnel are available, because no matter how special your MFC is, the guy is more important, and much more heroic than your MFC can ever hope to be. Never forget that.
The guy's eyes are Aryan blue. Period. No exceptions. No brown eyes. If you have two guys and insist upon giving one of them another color, make them green. Brown eyes, like brown skin are verboten in YA fiction except as minor throw-away characters. And you know that.
At least one of your guys must have hair falling into his blue eyes. I cannot overstate the importance of this. If you have the two polar opposite guys, then it must be the lower-class, bad-boy guy who has the blinding, eye-piercing hair.
The Inevitable Triangle
Two guys are better than one, and some of the ground rules listed here will have to be adjusted to make room for two guys. In this case, both guys are unnaturally and/or irrationally attracted to plain vanilla MFC instantly, and for no reason. The two must be polar opposites, one 'good', and one 'evil', yet the MFC loves them both equally and cannot possibly choose between them, often going back and forth between them as the plot dictates. She cannot survive without either of them. One of hot pair must be clean-cut, spoiled, wealthy, self-absorbed, and he is brooding, with a dire secret, whereas the other guy is lower-class, works with hands, has chiseled muscles and hair falling into his eyes, and he is brooding, with a dire secret. There can be no exceptions to this rule. This bad guy must touch the MFC inappropriately, and talk to her like she's his property, and she must never see anything wrong in his conduct. If he's an adventurer, his name must be Jack. At least one of these guys must stalk or at least creepily follow the MFC all around; he's always there, yet she finds no problem with this, nor even when she discovers he's watching, or has watched, her sleeping. The MFC is overcome by the wilts and the vapors and/or is unnaturally and/or irrationally curious about at least one of the trope dude(s), each of which also has non-standard issues just like the MFC. At least one of these guys has some dirt on the other which he fails to share with the MFC because she's just a girl. At least one of these guys, preferably the 'good' guy, must have gold flecks in his eyes.
You cannot possibly have a YA trilogy without having at least one (and preferably more) girl(s) who are outright bitches and who completely detest the MFC for no reason whatsoever. These bitches must serve no purpose at all other than to be bitchy. Ideally, one of the bitches has some sort of hold over, or dirt on, or a previous/ongoing relationship of some kind with trope guy.
If it's a school setting, the school lunches are invariably nasty.
As if YA trilogies aren't already embarrassing enough, at least one of the trope guys must catch the MFC doing something odd/ juvenile/ embarrassing/ sentimental. Ideally, this will be in an intimate situation where the girl is at least partially undressed, or is wearing a swimsuit. This activity is readily tied to the next one in the list for even greater trope and cliché.
Caught in the non-act
The couple is caught in flagrante delicto by the bitchiest girl in the faction/ group/ school/ town/ tribe, who now has 'dirt' on them. This is best used where the 'dirt' she has is so harmless or mild that it's quite plainly stupid to even make an issue out of it.
Evil That's Not
The MFC must, at some early point in the story, suspect at least one of the guys of perpetrating some evil act that turns out not to be evil, or that turns out to have been unavoidable (for example to prevent a greater evil), or he was set-up.
Out of Character Experience
Rather like the fictional out of body (OOB) experience, your MFC has to be presented with a challenge or opportunity that if she were playing true to her established character, she'd avoid in a millisecond, but which she takes on anyway.
Nomenclature (part two)
Minor characters must have calculatedly super-kewl names that border on the absurd. Don't even think about looking up likely names to match the birth year of your characters so you get something that's actually realistic. That's just plain stupid. Instead, come up with the most out-of-the-ordinary names you can possibly think of, no matter how stupid they seem. One easy ruse is to use family names as first names for characters, so names like Anderson, Bailey, Carter, Conner, Cooper, Ellis, Emerson, Kennedy, McKenzie, Morgan, Parker, Preston, Quinn, Walker, are perfect, but note that you can never shorten these names. McKenzie, for example, is never called 'Mac', Kennedy is never 'Ken', Preston is never 'Prez', Conner is never 'Con', and no two characters can ever have the same name because this never happens, even in real life.
The MFC must be somehow special, even in a novel that isn't fantasy or magical. She must have powers or traits which make her highly desirable for admission to clandestine organizations, or to save the world even though she's just a kid.
Don't Go There!
When it comes to 'don't go there' you must always go there in YA fiction. It's just stupid not to. If the MFC is warned away from becoming involved in a new, preferably risky opportunity/ endeavor/ activity or from visiting a location, she must ignore all warnings no matter what, and do the very thing she shouldn't, even if it's completely against character and makes no sense. Preferably she should be encouraged to do this and accompanied by the bad leg of the triangle. If you're really good, you can turn this event into a rift between her and the good guy, thereby artificially raising the melodrama of your novel.
No Adults Allowed
Whether she started out as a loner or not, your MFC must end-up in teen group which has little or no adult supervision. Indeed, no teen in your novel can ever really have adult supervision.
This group she hangs out with behaves uncomfortably below the chronological age of its members, and your MFC sees no problem with this no matter how grown-up and responsible she was beforehand. If you write this properly, you can make her naughty behavior be the cause of an accident, preferably occurring to the good trope guy who is heroically trying to save her from herself, and his resultant injury then causes her all manner of deep guilt.
Kissing (part one)
Kissing and intimacy must be indiscriminate and shameless. The MFC must end-up kissing at least one trope dude quite early in the story - preferably the bad guy.
Kissing (part two)
Shortly after that first kiss, your MFC must shamelessly kiss the other trope dude.
Kissing (part three)
Your MFC must slut-shame all other girls who do the very same things she is doing, but your MFC must remain a virgin no matter what.
Your novel must be racist or bigoted. Extra credit if you can do both. Thus, Dire Virgins has only good, honest, decent white folk in it, but it has two token people of African descent: Mox and Tokina (hence her name), and one Asian, Tatu, because of course tattoos and drugs can only be dispensed by Asians.