Teenage girl with younger sister who she is fiercely devoted to and will do anything to protect. Is this overused?
Depends all on how you spin it - what's your genre? are you putting a fresh twist on your plot , or are you rehashing what's already out there?
Hmm...relationships shouldn't be too cliche. But, maybe instead of younger sister writers could mix it up a tad, with a cousin, best friend, or aunt relationship. I love a good BFF story, being so devoted as to lay down your life for a friend. But, like Peachalulu mentioned it does depend on the story genre, that changes a lot. The situation and time period too.
Well, it's a futuristic story, which is part of why I'm worried about it, because of The Hunger Games. I don't want it to sound like a rip-off on THG.
I don't think a relationship should be a rip-off. Does your story have the whole battle to the death and against the government? Even so, it all depends on how you write it, it may not turn out to be similar after it's all said and done. Have fun writing your story!
Why not flop the characters? - make the younger sister be the fiercely protective one - I saw this done in an old ya book called Where the Lilies bloom by Bill Cleaver in which a set of orphans are managed - not by the sixteen year old sister whose too flightly and sensitive but by their resourceful twelve year old sister. There is also a post apocalyptic ya book called the Girl who owned a city - where the hero is a ten year old girl who takes charge - even though their are older children in her gang. Not that you should have to change your story.
Relationships, in my opinion, are hard to call "cliche" because, aside from some exceptions, relationships are a pretty key part of any kind of story. It's how you use the relationship in the story and what works with and off of it that can become a bit muddled or over-used. As for your example, I wouldn't call it "cliche" because that sounds very natural. An older sister being protective of a younger sister is almost expected in some cases. That's just biologically how familial ties work. Likewise, it's also rather unsurprising to see two sisters not like each other at all because, again, that's natural (at least, in the case of humans). I think you can easily get away with it, but possibly add some depth to it? Maybe there's a reason why the reader would think that the older sister shouldn't be devoted to the younger one whatsoever? If it's a sci-fi, there's a ton you could throw in there to make such a relationship a hard and stressful one.
There is no such thing as a cliche storyline. Everything has been done before, and there is always room for an often-used storyline written well.
Everything hasn't been done before... I can attest to that, because someone always finds a new way to be weird. I rather not get into details, but lets just say that a giant sewer makes for a really really weird and gross storyline. Nightmares for weeks kind. Sure the archetype or sub-type may exist, but after awhile you find some truly bizarre and original works. Anything being assumed 'cliche' obviously has been done before (in general to various degrees of specificity), but many readers are comfortable with certain 'cliche' elements because they are not 'cliche' and are simply plot devices critical to the genre or type of story. Its like saloons in westerns, sometimes the genre sets up the devices, if a brawl or even a fair amount of the storyline takes place in a saloon, then it shouldn't be cliche. Fantasy in magic, cliche, okie-dokie fine with me. Relationship type X, cliche, how many relationship possibilities exist anyways. 'Cliche is cliche' is more accurate. It strikes a nerve when people dismiss entire genres or storyline types as 'cliche' because of a basic plot element.