Originally Posted by Tet2I will second these tips. Chem healing is quite important imo.
Chem healing can be quite useful because they have really short recharge times.
Other than that turret or assault drone can be quite useful too.
The turret has more HP but I like the drone better because it can lure the enemy out from cover.
(But the drone has quite a low HP so they tend to get shot down if you use it when there are many enemies)