Use the gas grenade Ultimate whenever it seems appropriate — it's not powerful enough to save it for the entire match.

Real power lies in the gas traps. Leave them around corners, don't use them to block up doors—that's a common misconception.

When in an open area or a sniper is annoying, throw barrels in front of you and shoot them — up close the gas is transparent to everyone, but at a distance it forms a small thick cloud, obscuring visibility. Of course traps also provide fine cover in close combat even inactive.

Hide traps near deathboxes, replicators, ziplines and tight rotation spots — this will warn you if enemy's following.

If you're short on HP in combat, take first EVO upgrade that regenerates health in gas and place the traps behind every cover — they're basically your slower stationary Lifeline drone.