Been trying to practice Dash Dancing. It sucks because I've got twitchy hands, so I tend to make a lot of mistakes when trying to keep the timing right. Fun fact about this game: if you either press Down on the stick or release the stick entirely mid dash, you will return to a standing state. This is great for fighters who have bad dash attacks or grabs, because often their standing grab is a lot better, and usually they have a better attack to hit with. Another neat option is the Stilt, or sliding tilt. During a dash, pivot quickly and throw out a tilt. You maintain a lot of the dash momentum, and it can be used either offensively or defensively. The input is essentially the same as the RAR, but you don't jump.
Wavedashing is back, too, but it's a lot less useful. Dash dancing is probably the technique you want to master to take your game up a peg.