If you dash into an immediate shield dash, and immediately WD out of the shield, then do the same before the WD is over, the shield won't cancel the momentum the seconds time, but it will the first. It can create the illusion that your character can alter his traction if done back to back and followed up with other moves that add onto the effect. I'll put up a video of it being done correctly sometime or something. This is very old by the way, just realized I've never said anything about it. I may use this and a few more tricks in some scenarios and throw together a video. There are a few ways to make your characters...different.
EDIT: It's only good looking if you do it framer perfectly, which is hard at first with Fox. Try it with Falco and if you do it, you'll know for sure what I'm talking about. If someone does it good, put up a video, and throw it into a scenario or something cool.
EDIT 2: Also after the first dash into shield WD, if you moonwalk after the WD and shield dash fast enough, you can do it without a dash backwards and still not have the shield cancel your momentum one bit and show up. This one is much harder though.
Also every character can "Shine turn around" onto the ledge if they dash cancel perfectly and turn around wavedash. It's hard, to do because you have to have a loose control stick so you'll be able to dash cancel by tapping it down the slightest bit, then dashing the slightest bit and so on. Also very old news, but a lot of people probably don't know.