(Innate): Lux's damaging spells charge the enemies hit with energy for 6 seconds. Lux's next attack will ignite the energy, dealing 10 + (10 x level) magic damage to the target.
Gives Lux that extra damage in early game duels and is useful for making that last AA count for the killing blow and/or extra harassment. I feel like people put too much importance on this part of Lux's kit. Early game it is phenomenal for pushing your opponent out of lane but mid and late game it is much less likely that you can successfully execute an AA after every single ability. HOWEVER
, that doesn't make it useless mid and late game, in fact, a significant portion of Lux's damage still comes from her passive later in the game. More on that in a bit.
Q: Light Binding
(Active): Lux releases a sphere of light in a line, dealing magic damage to the first enemy it touches and half that damage to a second nearby unit. Additionally, the first unit struck is bound for 2 seconds, and the second unit for 1 second.
Snares! Not just one but two! Not as OP as Zyra's E and not as strong as Morgana's Q but a nice balance of the two, being able to go through the first target and snaring the next target it hits. An essential part of a successful Lux combo relies on landing your Q. It is also one of your "getaway" abilities. Snare and run!
W: Prismatic Barrier
(Active): Lux throws her wand to a target location and back, bending the light around herself and any friendly champions it touches, shielding them from damage for 3 seconds.
Much overlooked by most summoners, Prismatic Barrier actually provides a TON of damage mitigation. At rank 1 it provides a total of 160 (80 on cast and 80 on return). Which means when you and your opponent are level 4 (when I put a point into W) and they come in for an ignite (130 true damage) to finish you off your shield (160 hp) can completely absorb all of the damage. Cast the way you are running if you need to get the second part of your shield sooner or cast behind you if you need to have a longer duration of your shield.
Don't forget about using this Ability on you teammates! It can be hard to land but it can also save some lives!
E: Lucent Singularity
(Active): Lux sends an anomaly of twisted light to a target area, which slows enemies on the zone. The zone will deal magic damage to the enemies on the area upon detonation. The zone will detonate itself after 5 seconds or it can be detonated early by Lux.
Scout. Harass. Slow. Different situations call for this spell. As mentioned before, you should be careful about spamming this spell early game as it can push your lane. That being said, this is also your biggest form of harassment, so when you do cast it at your opponent, land it so it doesn't hit that minion wave, unless you want to clear/push your lane... then this ability can push your lane so you are free to: gank mid, gank top, get blue, steal blue, do objectives, etc. Don't wanna facecheck that brush? Scout with your ball first! Need to get away? Throw your ball between you and your chaser!
R: Finales Funkeln
(Active): After gathering energy for half a second, Lux will fire a broad and long-range beam of light in a line that will instantly deal magic damage to all enemies in the area. In addition, the beam will trigger Lux's innate ability and re-apply the Illumination debuff.
My favorite ultimate in the game. Long-ass range. Big-ass damage. One of the most overlooked part of Lux's ult is that it ignites AND re-applies
your passive! At level 11 that is 640 damage not factoring in ANY AP you've built on a target that has
on them. Learning how and when to aim this giant beam of damage takes time but it is also very forgiving with a 24 second CD @ 40% CDR and wider than animation damage area. Icing on the cake is that it illuminates the blast area so you can see what you hit.