When casting [C] Leer , you want to position it so the eye is at an awkward angle for the enemy you're swinging. This forces them to swing their cursor to the eye, shoot it, and then swing all the way back to shoot you.
When combining [X] Empress and [E] Dismiss, use your invisibility to reposition to an unexpected location. Consider where the enemies want to go, what angles they're watching, and what cover you can use to outplay.
When using [Q] Devour , if line of sight between Reyna and the orb is broken for more than 1 second, the heal will stop.
When using [X] Empress , you will immediately heal after killing an enemy without having consume, or to use [Q] Devour on an Soul orb. You also have unlimited charges of [E] Dismiss, which means you can heal and turn invisible after every kill.