step one: improved unarmed combat for all and for free
step two: everyone can buy as much jump as they want.
step three: find a copy of the "dragon fist" rpg. steal, steal, steal ideas. If you can't find that or don't feel like doing an easy conversion to d20 (consider it half way between 2e and 3e), Iron heroes with heavy armor removed works nicely for the genre. Great stunt rules and other conventions that just flat out scream wuxia. The Rokugan setting for legendof the five rings has some combat styles that could be given colorful names and made "stances" for the wuxia flair.
step four: use the oriental adventures book a great deal.
beyond that it's just a style of storytelling. Dungeon crawls are a bit counter to the theme for the most part. Over the top names for everything are a must. at some point the pc's must engage in a battle with some variation of "the axe gang". Oh, and hopping vampires, people that attack with all sorts of strange weapons, spoons, hair, rope, flower pots, did I mention hair? What I did to get people to be a bit imaginative in their weapon choice is reduce weapon stats to as follows: light weapon = d6 crit on 19-20, medium weapon = d8 crit 19-20, two handed weapon = d10 crit 19-20. that way a pc can use an unconventional weapon without being punished for not taking the optimal choice. I called hair an exotic weapon that used two hand weapon rules but allowed objects to be held in the hands but could not be combined with a shield. As a rule of thumb, if you don't see how something could be used as a weapon, it's an exotic but give it a little cool factor to reduce the pain of having to burn a feat to use it. like for a fan, regular, not warfan, make it a small weapon that lets the pc make "wind based" trip attacks and disarms within 10' with unobstructed line of sight. they can blow out candles up to 30 feet away but only within that one extra square can they effect anything with any real mass.
hand wave the fool who tells you "I hit twice for 35 pts of damage". It's the player who says things like "I sweep his feet out from under him and as he falls catch his shirt with one hand before he hits the ground. I stick my tongue out and if he moves to attack I'm dropping him." that must get the spotlight and bonus xp for cool. Do whatever you have to do to encourage creativity in your players. That's the only way to get a Wuxia themed game that feels right to me.