Always make sure you’re stood behind at least 2 minions so she is unable to root you with her Q.
If Lux uses her Q and it misses, use the cooldown of this ability to play aggressive as she will be unable to protect herself and prevent the all-in.
Mitigate Lux’s E effectiveness by standing behind and not inside the minion wave. This will make her choose between using her E to poke with or to push with.
Lux will often roam around the map alone to ward. You can ambush her and take her down before a major objective spawns and then quickly take the objective afterwards.
Lux excels at catching out enemies with her Q. Make sure your team is grouped together and no one is walking around the map alone as she can easily burst them down.
In team fights, try to engage as soon as possible. Lux will try to delay a team fight so she can poke with her E or get a pick with her Q.
Lux is really strong once she unlocks her Ultimate R. At this stage, she will be able to get kills and burst you down.
Once Lux has max cooldown reduction, her abilities will be on really low cooldowns. This means she’ll be able to poke and trade quite frequently. Do not get caught out by her low cooldowns.
In the later stages of the game, Lux is really strong and can quite easily take down any target if she lands her Q. Try and set her behind in the early game so she is unable to get tons of AP and snowball.