Avoid them like the plague. Considering that I was able to find, in about three seconds, a multitude of Google results for “clichés in writing,” it’s amazing to me that writers continue to use and abuse them (there’s a cliché or two for you in this paragraph alone).
There are those who go for the obvious phrases, like “stick out like a sore thumb,” “like a kid in a candy store,” or “breath of fresh air.” Others are more subtle than that.
http://authonomy.com/writing-tips/publishers-list-of-phrases-for-writers-to-avoid/ mentions the newer trend of “stock modifiers”—words that are commonly paired together that have become clichés of their own. Someone isn’t moved; he’s visibly moved. Another is woefully unprepared. Yet another is unfailingly polite.
Clichés don’t always have to be set phrases; they can also be storytelling clichés, as discussed on http://litreactor.com/columns/top-10-storytelling-cliches-that-need-to-disappear-forever. There’s an easy way to proceed, which usually turns into a cop-out. Describing your character’s looks by having her look in a mirror? Don't fall into that trap; be unique and don't follow the crowd. Is your character a bad guy? Blame bad parenting or past abuse. I’ll tell you a secret: the scariest bad guys are the ones who have no horrendous incident to blame. They’re just psycho and that’s that.