I've long been interested in writing a fantasy novel. Over the countless iterations I've gone through, one thing has remained clear: a quest for originality.
I know some people like the fantasy cliches, but a good chunk don't. These people want imagination, creativity, and originality. They don't want to meet an 'elf' and instantly know that it's a super-strong super-fast super-agile magic-wielding likely-vegetarian nature-lover with pointed ears. And I'm with them.
I have ever since been making my fantasy novel more and more 'original' by going against what might be expected. At first I had elves. But they often tripped and face-planted with everyone else. Then I made them super weak. Recently, I've decided that the very idea of elves is in fact a genre convention, and I have eliminated them entirely. The novel is now centered on humans. I went further. Humans are the only sentient race. There are no elves, dwarves, goblins, or any of the other expected races.
In fact, the only thing keeping the novel as fantasy at all is that it is set on a different planet, a lack of modern technology, and the humans use magic.
All of that is just an example. My question is, if I intentionally go against the genre conventions - for any genre, not just fantasy - where do I draw the line?
There has to be a middle ground somewhere. On one side of the spectrum you have knights, elves, magic, dragons, different species, and so on. Go completely original and you get something really weird, like telepathic super-platypuses swimming in the molten oceans of a lava world.
How do you know when you need more originality, or when you need more convention?
Edit for future viewers: I've marked the answer by Chris, because it explain the theory behind my question and its solution. I would however like to direct future viewers to Sara Costa's answer as well, because it creates - at least to me - a very clear line, and an easy way to tell how much is too much in terms of originality vs genre conventions.