* Do not kill the lesbian right after she gets into a romantic relationship.
* Avoid the offensive “magical Negro” trope by giving nonwhite characters backstories and motivations of their own.
* If you can’t think of any reason for your male character to Do The Thing than that a female character has died, scrap your male character and create one worth watching/reading about.
* If you have only one character of color, a) don’t kill them and b) ADD SOME MORE WTF IS YOUR PROBLEM.
* Trans people exist. No, really. They do.
* If your audience is angry and grieved at you, this does not mean you “got a reaction”. It means you betrayed their trust.
* Genocide is wrong, even if the race or species in question is ugly aliens. “But this alien/magical species is made up entirely of evil beings!” This does not mean your hero should murder them all. It means you need to make your aliens more complex and interesting and come up with a real motive for them. I will stop complaining about fantastic racism when we actually meet a species or subspecies that is all evil.
* People who have been severely traumatized are not just being stubborn and will not instantly get over it completely because they fall in love with the random heterosexual love interest or help your ragtag band to Do The Thing, thus getting back into the game.
* You are only permitted to write about a character committing redemptive suicide after you have spent a minimum of 100 hours volunteering for some kind of suicide prevention program.
* Are you male? Congratulations! You are completely free of any risk of creating a Mary Sue! Bask in that for a for few minutes. When you’re done, come back and let me tell you about Marty Stu.
* If your story would still make perfect sense if you cut your main character out of it, go ahead and do that and enjoy getting to know your real protagonist.
* If the only way your plot can move forward is if all of your characters are idiots, at least give them a reason to be idiots. Have them all accidentally get drugged or something. Actually, you should make some major changes in your plot if you have this problem, but if you can’t be bothered to do that, have your character swallow a Valium because he thinks it’s an aspirin or something.
* If you want your audience to view your protagonist as a hero, here are ways not to do that: have him be really buff and good at beating people up, make sure all the female characters want to bang him, have the moral worth of other characters be determined by whether or not they benefit him. Here is how to do that: have him do heroic stuff. You know, like save people’s lives just because it’s the right thing to do, with no expectation of reward.
* Contrary to what Hollywood seems to believe, most people over the age of 12 are able to put aside personality conflicts enough to work together reasonably well, at least for a short time, like the amount of time it would take to put together a Powerpoint presentation or stop a meteor from annihilating the Earth. We do not need another story arc about a ragtag band of grown-ass adults “learning to work together”.
Feel free to add your own.
All this.
Avoiding crappy cliches is pretty easy when you spend some extra time on making your characters complex so that you can drive the plot from a new and different point of view!