Don't poke too much, you're losing a lot of value you can have by being behind the enemies.
STOP fanning the tank after you ignite! It's okay if it's the end of the fight basically and he has no supports. If you stand in the frontlines for too long you get immediately thanos snapped.
STOP engaging with dancing blaze! It's your most important and risky ability it gives off your current location which tells everybody you just engaged giving them enough time to turn around before you've done vital damage. Also you need it so you can parry; cass nade, ana sleep, ana nade, brig whipshot, ALMOST every ult in the game!!! reaper dire triggers and sniper shots.
STOP picking the longer fire perk! not only are you giving supports free ult charge but you're also passing on a significantly better perk, heat shield. Supports not healing you before you ult? Just ult. You're in a sticky situation where everyone is on you trying to kill you? Just ult.
Speaking of ults, STOP reviving!!!! I can't stress this enough stop feeling tempted to self revive just because they're "one shot" or whatever. It's the worst ult in the game. The only time id allow a revive if it's overtime and your revive is directly on the payload. but the moment you get ult you're supposed to use it no matter what in overtime so what are you exactly waiting for?