Man, there are still at least two HUD elements that I don't even have the slightest idea about. I couldn't beat the rapid cancel tutorial and haven't tried any tutorials past that yet. Beating the story mode seems feasible and maybe I'll find something less completely absurd to play by the time I've finished the game.
I put in BlazBlue CS myself when I saw this post to try the tutorial and see if I could help. It looks like it tries to make you rapidcancel as part of a big combo instead of just teaching it to you by itself so that's kind of dumb. :\
Here's the combo, don't worry if you don't understand my weirdo fighting game notation!
B xx C xx qcb+A xx RC, B xx C xx qcb+A, qcb+D
It does an easy rc lesson right after that that really should have come first:
dpm+C, RC
My advice: hitting A+B+C on the Vita is going to be awful so
sell it and buy an arcade stick bind the command to L or R or something.
The combo makes you do
B, C, quarter-circle-back-A
twice, so think of it as one chunk, and maybe do it a few times by itself to warm up and get it in your muscle memory.
Then actually just start doing it twice!
B, C, quarter-circle-back-A
hit the rapidcancel button
B, C, quarter-circle-back-A
and then just keep doing that, and when you feel like it, add quarter-circle-back-D at the end and finish the tutorial. The next one is just a dragonpunch motion (z) and C, then a rapidcancel to make it safe (so that Ragna doesn't leave the ground after it hits).
Hope this helps, and that the tutorial on the Vita isn't arbitrarily different or something!