Do you mean clichés or tropes? There's a BIG difference. Sometimes, it's good to use heavily-used tropes. If it ain't broke, don't fix it.
Simple. Make the protagonist an intelligent unassuming guy without super powers coming out of his ass. Making him strong is fine, but he shouldn't be the strongest, and he shouldn't be pulling powerups out of his ass all times, or your supporting characters and villains will lack credibility.
This is easy. If you HAVE to do a tournament, be smart about it. Like, YYH's Dark Tournament bored people to tears, but I personally thought the Shaman Fight in Shaman King was done very well. Rather than FIGHTFIGHTFIGHT, they traveled to different locations, met new people, had all sorts of different fighting conditions, etc.
Also, don't be afraid to kill off characters and don't be afraid to end while you're on the top. Which doesn't mean that anything longer than 10 volumes blows. Look at Kenshin. That was 28 frickin' volumes, and it's one of the best Shonen of our time. Better than the current "big three" to be sure.