Tropes are what make stories run. A story is not good or bad based on whether or not it has tropes. ALL STORIES HAVE TROPES. A story is good or bad based on how those tropes are used.
What we like about tropes is familiarity ("Yay, ninjas!"), excitement ("Oo, the hero's going to get all awesome on the badguys!"), and especially when our favorite tropes are twisted in interesting ways ("I did NOT see that coming").
What we don't like is when tropes are predictable to the point of boredom. That's when a trope becomes a cliche.
Now, cliches are subjective. What's old and tired to you may be brand new to someone else, or it might be someone's favorite trope--they don't care HOW much it's been done; they love it every time. So how do you keep your stories from slipping past trope into cliche? Here are a few ideas:
- Be trope-savvy. One of the things I loved about Avatar: The Last Airbender was how it was always aware of its own tropes. Sokka knew he was the comic guy, the plan guy, the boomerang guy, or "the guy in the group that was normal." They knew they were being silly (and yet a little bit serious) when they came up with a name for their group or for the bounty hunter Zuko sent after them.* It worked because they showed you they were aware of their tropes, through action and dialog.
- Subvert the tropes. I thought Megamind was fantastic because even though it used all the superhero tropes, it never played them straight. It took one of the oldest tropes (villain captures girl, threatens hero, hero outsmarts villain), showed they were trope savvy (girl mocks villain's threats as cliche), then twisted it (villain kills hero?!). And that was where the movie started. That sort of thing kept me guessing the whole time, even though I knew the ultimate end.
- Don't bother. Seriously, the subjectiveness of cliches is one of the reasons you can't please everybody. One completely viable method of dealing with this is to not even try. Use the tropes you love, put them together in ways you think are awesome, then find the people who agree with you.
* And the fact they never tell you his real name proves even more they know the tropes they're playing with:
Sokka: Wait, YOU sent Combustion Man after us?
Zuko: Well, that's not his name, but--
Sokka: Oh, sorry. Didn't mean to insult your friend!