Wow this thread has been really helpful for my masquerade hope! And it's also now put a bit more pressure on my masquerade hopes...
I really like going in the masquerade, been it it a couple of times, and I generally do in character walk ons, with music.
The first time I was in a masquerade, I was Dark Woods Circus!Miku Hatsune. I surprisingly won best characterization! The I walked on Daughterof Evil!Rin Kagamine and that wnet well and audience seemed to like it enough, even it it didnt win anything.
But then one time I was normal Miku, and I attempted to lipsync and dance one of her songs, and it turned out to be a rather a disaster...
So yes, agreeing to all the Dos above of adding music and character and poses to your walkons, and to practice practice!
also, other advice! For backstage in the greenroom, DO bring nourishment if you can and if you're wearing a thin costume bring a sweater. You'll be there for a while. I remember last year at AX I ended up starving and the air conditioning was freezing. Also bring something to entertain yourself while you wait, but you can also use that time for some last minute practice!
also, DON'T despair if you don't win anything.What matters is that you went out there and gave it your all and had fun and the audience enjoyed it