Hi!

Dont use this build until you get to know Lux.
Its a quicky guide for Lux. This is the way i play her i wont write a fairy tail about her.
This is not the way you have to play Lux.

Do w/e you want, but i use these against ap champs, ofc against ad like zed or yasuo i put armor instead of mr.

This the my standard build. If you cant play defensive dont buy mejai.
Against tons of ap buy abystal.
I use forbidden idol for farming, without it you d run out of mana quickly. After mid game you can sell it to buy some hardcore item.

Pros:
High range, you can farm without risking you lil blond life.
AoE dmg.
Barrier and W will save you little life.
Ulti is awesome.
Shield your little side btches.
You can roam and catch bot lane at the same time wow.
In a narrow place you can easily win a tf.
You can start a fight with a Q.
You also have a spell to run away from jungla.
With luden you can steal Drakes.

Cons:
In late game your damage wont big Wow.
You can easily miss you skillshots so train a lot ofc in ranked matches.
In early not the easiest champ to farm minions.

I always use shield (W) on smartcast so i can react fast.

If your team is ahead try to catch people with Q from behind the wall and in teamfight stay behind and sometimes protect adc.