The long range of Lux's abilities allow her to zone and generally counter short-ranged champions.
If you hit an enemy with Light Binding, throw a Lucent Singularity but do not detonate it until you land an autoattack. This will allow you to ignite two Illumination charges for extra damage.
Lux can be deceptively durable using Prismatic Barrier. This allows her to stay alive in team fights much longer than expected.
Use Prismatic Barrier in teamfights, granting your entire team a strong absorption shield.
On cast, Prismatic Barrier will instantly cast the shield on you, and when the rod returns it resets the shield on yourself. When running, cast Prismatic Barrier in the direction you are running. This way, you will be shielded twice, faster.
Lucent Singularity provides sight. Use it to check bushes or gank spots before approaching to prevent an unnecessary death.
Use Lucent Singularity then auto attack , then while your auto attack is in the air detonate the spell. That way you can get the Illumination passive to detonate right after.
Using Final Spark to hit enemies who are attempting to Dragon or Baron Nashor may allow you to scare them or even kill steal the Dragon kill or the Baron buff. Similarly, it can be used to finish off the monster when your team is attempting the kill.
If Lux is used on the map Twisted Treeline, her ability Final Spark from the middle brush can target enemies at the tower. This gives Lux and her team an advantage in lane control.
It is advised for Lux not to get into a close-up fight, as her low movement speed, long cooldowns, and relative fragility will work against her. Stay behind your teammates and spam spells into fights from afar to stay out of harm's way.
Lux benefits from cooldown reduction more than most champions, as her spells are on a longer cooldown than most caster champions. Try obtaining the Ancient Golem buff to use Final Spark as an effective poke ability.
Having a strong map control or Clairvoyance is an effective way to see enemies in the fog of war, allowing for well placed/timed Final Spark on low health enemies or epic monsters.
Final Spark is great for clearing large amounts of creeps in a lane, and harassment in lategame due to its ridiculously short cooldown.
Feel free to use Final Spark just to shave off some of your opponents' HP, due to its cooldown and high damage output.
At 40% cooldown reduction Lux can perform it every 30 seconds , which is so low that she can use it to soften up enemies in a teamfight and then finish off any escaping opponent
The damage of her ultimate Final Spark extends slightly past the targeting icon, but enemies will likely dodge it if they are at the very edge.
Lux can easily punish enemies who overextend or chase her down by kiting as it's easy to have them go through your Lucent Singularity especially in the jungle, will make it easy for you to use Light Binding and your Final Spark right after for damage which will either scare them off, finish them, or burst down their hp enough for your team to finish them.
However, Lich Bane synergizes well with Illumination, and is a great item for boosting Lux's burst damage potential.
Lux has prime lane control, making a Catalyst the Protector very useful to ensure dominance giving Lux enough health and mana. This can later be built into a Rod of Ages, granting a fair amount of Ability Power while giving Lux a good health pool should she be focused. The mana granted is also useful to stay in fights longer.
As Lux can stay relatively far away from a teamfight, AP should take priority over survivability. Rabadon's Deathcap is the most efficient way of doing this, making all her spells much more potent.
Since Lux's abilities have long cooldowns, cooldown reduction is crucial to her utility/damage.
Since Lux'sFinal Spark, has a relatively low cooldown and long range, it is best to stack up on AP and cooldown reduction to make it more potent and effective in weakening enemy champions before or during a team fight. Final Spark can also finish off enemy champions on low health that are retreating.
Building Archangel's Staff will grant Lux a fair amount of mana and ability power, allowing her to spam her abilities.
Since Lux generally stays behind her team in team fights and she can survive random chases due to her crowd control abilities, you can get Mejai's Soulstealer and manage to keep your stacks high, giving you a fairly high amount of AP and an edge over the opposing team.
Be careful when you have the Illumination debuff on while Lux fires Final Spark as you will receive both the damage proc from the Illumination and the laser itself.
Move away from Lux until the Illumination debuff wears off to reduce the damage you will take.
Do not run in a straight line when running away from or chasing Lux. It is best to sidestep to avoid her Lucent Singularity or Light Binding.
Prismatic Barrier does not do any damage, thus you do not need to dodge it. However, be ready to dodge Lux's other skills.
Due to the small and narrow paths in the jungle, Lux's spells become more than likely to land, enabling her to fully use her combo, which can devastate any carries or squishies.
This also becomes a problem / advantage in team fights that occur in these areas. Lux can easily deal massive damage to enemies who stand in a line.
Lux'sPrismatic Barrier is also more than likely to hit, shielding all her allies which will cause a large problem / advantage, preventing a large amount of DPS dealt to her team.
Lux is generally countered by champions that can survive her burst and chase her/close the distance, such as Wukong.
Lux is a skill shot based champion. Though her abilities move rather quickly, it is still possible to dodge them. However, Final Spark moves quickly; using flash to escape being hit by this may be necessary.