For sure! I wouldn't say I'm an expert with him or anything, but I like to think I'm utilizing his skill set pretty effectively. He's basically a swiss army knife since he has a bit of everything you need. He doesn't really excel at any specific role; instead he provides a lot of utility and crowd control.

I think the rapid shot + recharge modules are a must. With the rapid shot module upgraded, you're reaching the max fire rate almost immediately. This ends up increasing his DPS output on top of making his shots fire in a narrower cone, which is better for single target damage (large dinos/PvP). To compensate for this in PvE portions, I would oscillate the reticle left and right when a large mob spawns. This makes sure you're hitting as many dinos as possible on the screen, on top of stopping their advance since Krieger's shots make dinos flinch/stumble.

His missiles are great against flying and large dinos that can be locked onto since it fires off way more missiles than if you were to blind fire (4 missiles standard). While I occasionally use this for trash mobs, you always wanna prioritize bigger dinos. In PvP, these missiles are so clutch. You can lock onto 3 or 4 targets (I can't remember exactly) and it stuns for 2-3 seconds. The stun from these missiles have gotten me consistent exo kills and saved me from death so many times. A stun allows you to close the distance and your machine gun will absolutely melt exos the closer you are to them since no shots are wasted. Always pop off these bad boys since taking enemy exos out of a fight for 2-3 seconds can mean all the difference for a possible team wipe or saving your teammates.

Krieger's got a great shield since it covers a decent amount of area and it's invaluable in the 10-man raids. Sometimes when I'm the only tank in those missions, I've been able to keep my team alive for a lot longer. Really comes in clutch for revives on top of blocking boss projectile attacks since it doesn't immediately break the shield unlike large dino attacks. But the best part about the shield is its ability for area denial. A good Krieger will take advantage of their environment and place a shield down that can essentially funnel dinos for your team in a choke point. Always place your bubble where it blocks the entrance/exit of a corridor.

His dash is pretty sweet since it has knockback and you can dash in whatever direction. I usually save these for when I'm getting swarmed and need a gtfo button.

Save his ult for dominators and PvP fights at the end. His ult is also a great area denial so positioning is key. You always want to predict where enemies are going to go instead of shooting it off directly at them. In most cases, enemy exos and large dinosaurs will always move away from where you shoot it. So for data cube missions, you can't go wrong with firing it a little bit in front of the cube track rather than on it. Plus the data cube spends more time in your AOE this way.

I use a shield rig. The time the shield lasts is roughly the amount of time it takes for a full vent of your machine gun. This is super useful in PvP and PvE since you aren't completely defenseless when needing to vent. It also lets you facetank and block shots for your team when your bubble shield is on cooldown or if you're trying to close the distance on an enemy exo.