Specialists make good candidates for carrying Skulljacks due to their naturally high hack score allowing for more regular successes in using them. The extra hack boost from Skullmining is also the most useful on Specialists.
Giving a soldier Threat Assessment before he/she is opening fire as part of an overwatch ambush will result in the said soldier firing again after the squad loses concealment. This allows for an additional shot in an overwatch ambush.
Aid Protocol cannot be used twice on the same target.
Combat Protocol and Capacitor Discharge both bypass armour.
Combat Protocol and Capacitor Discharge both do not apply a damage bonus to robotic enemies that are hacked with Haywire Protocol.
Robotic enemies hacked with Haywire Protocol do not need to be destroyed to complete a mission that requires all enemy units to be eliminated: you do not receive their wrecks this way, however.
Robotic enemies hacked with Haywire Protocol, such as MECs, cannot act on the first turn of being Hacked but can act on the first turn after hacked ends. However, ADVENT Turrets can act on the first turn of both situations.
Revival Protocol used on disoriented ally that used both worse actions will give next two normal actions.
Ever Vigilant will trigger so long as you do not consume an action point with an action other than moving; it will trigger from skipping your turn, moving once, moving 3+ times, opening/closing as many doors as you like, or moving twice after using a Free Reload.
Giving a Specialist the Threat Assessment buff followed by making him enter overwatch will grant him two overwatch shots. Combined with Guardian this will usually grant 3+ overwatch shots in a single turn.
A hack attempt may be greatly sped up by left clicking begin hack and quickly right clicking twice. This will also refund the cooldown on Haywire Protocol if timed correctly.
Aid Protocol, Medical Protocol and Scanning Protocol each only consume a single action and will not end your turn. However Restoration does end the turn.
Hacking an ADVENT Network Tower or a mission objective only consumes one action point and will not end your turn. However hacking a robotic enemy with Haywire Protocol does end the turn, as do Combat Protocol and Capacitor Discharge.