How can we avoid them? Well, I don't want to say "avoid" so much as I want to say "be aware of." Cliches are fine, and totally normal considering they're just a part of life and of human perception. However, when cliches are being employed without realizing it or without being smart about it, writing gets dull and painful and nobody wants to read that!!
Considering the popularity of YA Dystopian fiction these days (think Hunger Games), I thought this was really funny! You can see all the ways that dystopian literature just falls into cliche after cliche (especially in the case of Divergent)
I mean, just take at this video: an Honest Trailer for Divergent! It's so clear that the book and movie fall into just too many cliches for it to be taken as more than a trendy, and thus popular, book/movie.
How to use them well?
Now, tropes and cliches aren't always a bad thing. It's just all about using them WELL! They help readers understand and have expectations for certain genres. To avoid the "cliche" aspect of it, I think it's more about execution and carefully structuring/subverting some of the expectations. Kind of like salt, just use a bit, not too much, to make it work out in a way that readers!