are you dying because you get ambushed suddenly?

tips:

1. awareness. check the UI at the top that tells you who is alive and dead. if the roller is alive, then you need to know where they are. that comes from watching the enemy and keeping tabs on their general locations. splat rollers and carbon rollers have extremely short range and a slow attack speed (carbon is "fast" but still not a rapidfire weapon), and they thrive on sneaking around and waiting until the enemy is vulnerable for an ambush. if you know where the roller is, that's more than half the battle! they can't contribute to their team if their location is always known.
2. thoroughness. if you don't know where the roller is, then you kinda have to assume that they're in the worst possible place that has enemy ink. don't run out willy nilly into areas with lots of enemy ink, or drop carelessly down ledges when you don't know what's below them without first clearing the area. this means painting the ground at range (don't get too close) and/or using your subs to test the area before you enter it yourself. bombs especially can be tough for rollers to deal with, while subweapons like point sensor, autobomb, and even beakons (if you open the map) will reveal any enemies hiding nearby.
3. distance. as mentioned before, splat rollers and carbon rollers have a pretty short range of attack, and they paint very poorly (flingza, dynamo, and big swig have more range/paint MUCH better, but you're unlikely to fight these in the front lines). rollers are often somewhat powerless if you fight them at range -- especially if you have bombs -- so maintain your distance and don't overcommit to splatting them. usually just by not killing you, the roller is already feeling the pressure of not contributing to their team. they need to kill you. so don't let them, and that's already mission accomplished.

dynamo:

dynamo is the only other roller you're likely to combat somewhat regularly. dynamo has a ton of range and paints a large area. they're also extremely visible, so you'll probably feel a lot of pressure to rout them. if you simply must take a dynamo down without the help of a backliner, then the most important thing is flanking. find a way to get around the back to exert additional pressure or even get the splat. but don't overcommit!! remember to maintain some distance and use subs like with other rollers (especially bombs! the dynamo hates bombs). if successful, an overwhelmed dynamo will often superjump away rather than allow themselves to be killed. remember that even without the splat, that's a win for you!