I'd definitely call Lux a glass cannon. Standard itemization involves Sorc Shoes, Athene's, Deathcap and Void Staff, with maybe a Doran's Ring or two thrown in. The tankiest item you might see on Lux is a Rod of Ages. Lux's skills don't make good use of Rylai's slow, most of her damage happens outside the range of Abyssal Scepter, and Zhonya's is not a good fit because being frozen in place doesn't do anything good for her. According to the wiki, she has the 3rd lowest starting health in the game. Lux's defense is positioning and controlling space with her long ranged abilities, if that fails she dies quick.
Originally Posted by BoneSentry
Lux is one of the more annoying champs because she can effectively stun you for a good amount of time, nuke you, and then ult you. If she is built in a certain way she can become a real powerful glasscannon that can seriously hurt you or stun you. That's kind of where her benefits end, she has her kit like others.
Just like i said, she's KIND OF a glasscannon if built pure AP, which makes her pretty vulnerable to counterattacks. If you notice she's being built as such, tell your AD carry to focus her down, and she will drop like a sack or potatoes most of the time. Since when she's built as a AP, she is usually a 1 person nuker and cant focus down more than 1 person, so try to pick her off and lure her into attacking the tank.
If she's built more support, then she won't be as much of a threat rather more of a nuisance, since she won't be eating your health as much. In this case you won't focus her before other champs, and building mr will probably be enough to counter her damage. CC and silence on your team will probably shut her down, so keep that in mind.
Other variations of her build have their counters, just think a bit.
In either case, Lux's offensive capabilities are pretty AP orientated, so building magic resist will greatly help you trade with her better and survive her attacks. Also, consider building some anti-cc like Banshee's Veil or Quicksilver Sash to slip by her stuns ( what a coincidence, BV covers both
). Other than that, play smart really, and avoid her laser
Lux does not have a stun, she has a root. This distinction might sound pedantic at first, but is a very important in some match-ups. For example, if Katarina blinks and ults on top of you, Lux's Q will not interrupt the ult. People who are rooted with Q can still do damage to Lux, provided they are in range.
AD carries are not good at fighting Lux, if she is being auto attacked by one at the start of a team fight then one of the two is grossly out of position and will be dead in a moment.