Use the bugs' fear of explosions against them.
Anticipate friendly movement (walk behind, not in front)
LISTEN to your teammates. The Dwarves have many voice prompts and unique sound effects. Example: If the engie hears the scout shout "Lights up!", the engie should be checking the lit area for difficult to reach materials to platform.
Environmental hazards - electric crystals, slime, and so on - affect the bugs too.
Balance ammo consumption. Ammo drops give 50% to all, so swap weapons for maximum gain.
Know when to use the terrain scanner.
Kiting Praetorians 180 degrees is powerful and requires no ammo.