- Expanding your squad size is probably the single most important tactical upgrade. Make this urgent.
- Another seemingly urgent upgrade allows you to get a random ability on soldier level up. It appears a soldier CAN get one, but it is not guaranteed by the time they reach max level. Also, as far as I know they can only get one of the bonus random/secret abilities (I got rapid fire, lightning reflexes...and kill zone which doesn't seem to work with my Ranger's shotguns.)
- Successfully hacking (once a mission) raises your specialist's hacking permanently by 5(?).
- Supplies are the bottleneck for upgrades. I sell a lot of things...including Intel, on the black market. Be careful as there are certain projects tyat require these items (such as corpses/elerium etc.)
- Some enemies have a lot of armor. This acts as a -damage on any source. Grenadiers with shred, and certain grenades (acid), or ammo (armor piercing), or PSI damage abilities can help reduce or bypass this.
- Kill the enemy PSI user to end mind control, psi-zombies etc. If you succeed in freeing your mind controlled squady, they get their actions for the current turn activated.
- Snipers are finnicky about what actions they can use, and still fire another sniper rifle round. (Kill Zone, Rapid Fire, free reload, grappling hook(!!!), and Serial work for example)