If you are about to do something dangerous, tell the queen to start watching you before you go in so she can heal you when you need it, rather than screaming "QUEEN HEAL!!!" and hoping the player is fast enough.
Acid spit does do some damage to cades, you can use spit and slashes at the same time to take down cades faster.
Acid spit also can go over cades. Spit on sentry guns, teslas, and flamer sentries without even getting in range of them.
If you are a drone or hivelord, always emit recovery pheromones, as you will not usually be on the front line, and other xenos will pull back towards your location for faster healing and cover.
For queens: Make Warden Praetorians your leaders. They have their own pheromones, so you can have them double up with Warding and Frenzy, for example.
For queens: Spam Word of the Queen as often as you want. It has no cooldown and makes a loud noise every time, which will make the xenos pay attention to it.
Base praetorian can use it's ground acid spray and then dash into the acid as it is spreading to extinguish itself.