Accuracy is king. Running around like a 5 year old firing blindly will get you killed first. Take your time (if you have it), line up your shots and do so from somewhere defensible, if you can.
There is usually a chest sensor. This is a massive target. You should avoid having your chest ‘open’.
Any gun is far steadier when held with two hands in a stable configuration. The best way to achieve this in laser tag is to have the gun properly supported by one hand, while the other hand takes care of the trigger and buttstock. It’s far stabler when you shoot down the line of your shoulders. This has the added benefit of essentially hiding the chest sensor under one of your arms. Some might consider this unethical, but it’s the posture used by soldiers.
Walking shoulder-on basically reduces the number of sensors visible to enemies along your line of sight to one – the shoulder sensor.
These things will save you from a lot of deaths.
Don’t forget, like the others said, to use the cover you have. Moreover, don’t forget to watch for people flanking you. The last thing you need is for someone to shoot you in the back while you are engaging someone else at range.