Leave E sitting on the minion, escape lane, or choke long enough to tax movement, because Lux gets much cleaner Qs when the slow field forces one obvious path instead of cashing out for one fast poke number
Cash passive in lane after safe E hits and nonlethal Qs; a lot of mid Lux damage disappears when you cast like support Lux and never walk up for the marked auto
At 6, use R to erase the cannon wave and steal the reset or first move, because Lux is unusually good at turning a solved mid wave into a lit river entrance without having to win a fair footrace into the skirmish
Use R on the wave when clearing it changes the next 20 seconds of the game for you: cannon waves that buy a clean recall, waves that let you move first to dragon or river, or spots where the enemy wants to roam and you can pin them under tower instead. The mistake is saving laser so long that you lose tempo and then cast it only as a low-odds snipe. If the wave is already solved with E and autos, keep R. If clearing with R gets you out first and lets you place E on the next entrance before anyone arrives, that is usually a very good laser.
Lux's damaging spells charge the target with energy for a few seconds. Lux's next attack ignites the energy, dealing bonus magic damage (depending on Lux's level) to the target.
Lux releases a sphere of light that binds and deals damage to up to two enemy units.
Lux throws her wand and bends the light around any friendly target it touches, protecting them from enemy damage.
Fires an anomaly of twisted light to an area, which slows nearby enemies. Lux can detonate it to damage enemies in the area of effect.
After gathering energy, Lux fires a beam of light that deals damage to all targets in the area. In addition, triggers Lux's passive ability and refreshes the Illumination debuff duration.