< Marvel vs Capcom 2 | Roll
Strategies
Roll is a joke character in Marvel, and as such is almost impossible to use competitively. She doesn't do much damage and she has nothing really to abuse. She works OK with Tron's Projectile assist, as all low tier characters do, but that's only if you get Tron to do the damage for you.
You may be able to annoy them by mixing up slides and throws, but it doesn't do much damage.
Advanced Strategy
Pick someone else.
If you really want to play Roll, though, pair her with some decent assists. They won't make her god tier or anything like that, but if you've read this far, it ought to be clear that you'll need all the help you can get to play Roll at a high level.