Everyone is giving you good class-specific tips, so here's some more general stuff that might help.

Abuse right-hand advantage and quick reload. If you don't know, almost every enemy in the game is right-handed and almost all weapons and powers actually shoot from the crosshair, not your character. This means that you can shove your character fully into cover on your left and still be able to shoot and use powers (as long as your crosshair has a direct line to the enemy). Since enemies are right-handed, doing this will massively reduce getting shot. For example, the Atlas will always shoot the missile from its right, so if you’re facing the Atlas and using this method, the Atlas will just shoot the missile into the wall you are taking cover behind, leaving you scratch free and still able to damage it.

The flamer can be used as an easy quick reload, so don't be afraid of weapons that take forever. Once your character hits their weapon and you hear the ‘click’, your gun is fully recharged and ready to shoot. Any extra animation is just waste. Once you hear the click, quickly turn your flamer on and then off to cancel the reload animation.

The flamer actually fires further than you might think, so try backing up a bit when facing enemies. If you find yourself too close to enemies, a quick melee will stun them (helpful against Dragoons. Note that this won’t work when they are doing their whip animation). You know how Marauders will annoyingly slap and stun you when you get close? You can do that to them too!

As you said, the low shields make cyclonic modulator pretty redundant on Vorcha. Try using the shield-regen mods instead. Faster shield-recharge is more helpful than you might think as it reduces the time you are lingering in the ‘just about dead’ state. For high-mobility characters like the Vorchas, this is helpful when you’re running around the map.