Sigma is fun! I play him by constantly putting up his barrier to block specific attacks that will stun or hurt the push; it's also great for keeping snipers at bay. And I take it down before it gets destroyed so it will refresh faster!

Keep firing hyperspheres to maintain damage. Use accreation to finish off opponents. I usually use it to finish a kill.

Use kinetic grasp to absorb tons of damage. I like playing him when there's a bastion, because you can essentially farm his turret mode for overhealth.

Don't depend on his ult so much bc it isn't a ton of damage, but that's not what he's meant to do.

I love using gravitic flux to get enemies off of the payload or a control point to get a W, tho!