One thing that I've noticed when I prep for my Wandering Heroes of Ogre Gate campaigns is I make way more NPCs than in other settings. This may have to do with my own approach to the genre, but I also think wuxia by its nature is about people and you need lots of characters to make things work.
Anyone who has watched even just a few martial arts movies, knows that many of the characters are defined by narrow personality traits and a particular Kung Fu skill. Taking this approach has helped me, because the players face so many bit-player foes, I don't want them all to disappear from their collective memory, I want them to each stand out starkly and be memorable. One of my starting points is their martial nickname and the one or two key Kung Fu techniques they are known for.
Nicknames in wuxia are important. They help encapsulate the character. In Heavenly Sword and Dragon Saber, one of the more interesting characters is Golden Haired Lion King, and this immediately gives me a clear image if I am a GM of what kind of personality I am dealing with (someone powerful and boisterous). I try to find names that help shape my selection of Kung Fu Techniques and give me a clear handle on the character's personality. Because I am juggling lots of different underlings, foes, and vengeance seekers, it is important that I have this mental short cut during live play.
Selection of Kung Fu Techniques is quite important on its own. In Wandering Heroes of Ogre Gate, every martial hero gets a number of special abilities called Kung Fu Techniques. These are more than your standard kicks or sword-blows, they are extraordinary attacks that draw on a character's Qi. With a Kung Fu Technique you can do anything from diving into a whirling attack with your sword to unleashing a a wave of Qi energy with a roar. Presently all characters start with 6 Kung Fu Techniques and can gain more as they earn Experience Points. When I am making NPCs, I like to include a list of all their techniques but single out their signature techniques for paraphrased text from the entries. This makes it easier for me to use the techniques in a fight, but it also gives me a clear idea of what their opening moves might be. I try to fit the techniques to the NPCs personality.
All this is important because I am making so many characters for the game. Whereas in a typical Sertorius session I might make 1-3 major NPCs per adventure but spend the bulk of my time with stuff like mapping, with Wandering Heroes of Ogre Gate, I am easily making 2 to 3 times that many characters per adventure. There are still locations to map and items to describe, but you often have multiple competing groups converging on these places or going after the same prize.