I suspect few people reading this don't know about TVTropes, one of the few sites that gives Wikipedia itself a run for the money in the Where Did The Time Go Dept. It's also easy to read it, to ignore the very advice the site's creators give about it (tropes are not bad, they're just ingredients to be used for well or ill), and to go on a mad Trope Purging / Subverting Spree in your own work. Or to look at other people's work and crush it under a critical thumb because it dares to employ hoary old cliché X.
Back in my salad days as a writer I took a few pages to pound out a short story about a future where creative exhaustion has become so complete that nobody bothers to create anything new anymore. Instead, everyone's become a critic or a collector, trading back and forth but never bothering to actually read anything because they already know how it all works out. The story's since been lost to time and entropy (and bit rot), but I think about it whenever I see how enthusiastically people have taken to singling out, labeling and picking apart everything that comes to them along the cultural conveyor belt.
The best way to approach TVTropes is as a kind of museum. You see what else has been done, and you look at it with a bit of distance and remove. By having that distance artificially inserted between you and the other thing, you get a better idea of when it works and when it doesn't. This is more than just the whole "there is nothing new under the sun" argument; there are new things under the sun, they just consist of the old things in unexpected arrangements. The trick is being able to liberate your own vision so you can in fact see the David in that eighteen-foot-high slab of useless marble that once sat in Michelangelo's studio.