Never been in a tournament, but I always tend to go for Luma first. Even if she shields, it doesn't protect the luma and a single hit over the edge will get rid of it for 11 seconds or so. She can't camp you since her only ranged attack is a luma shot which can be countered and puts a large portion of her power at risk, which means she has to approach you herself unless you're already offstage. The invisible rolls can be annoying and hard to read so I'd stick to jabs until you have her in a bad spot.
She's pretty tall and floaty so she dies easy if you send her straight up, and her disjointed aerial hitboxes don't cover her diagonally so you have the edge there. Her up b recovery does no damage, so if she has to use it to reach the ledge you can drop down and try to spike her without worries of her hitting you first.
Don't grab her if her luma is attached since it will just knock you away. You outrange her in every way if her Luma isn't around so abuse that.
Not much else I can say.