As we know, Lux is great champion and she is famous for her laser. I just love her laser. Here is a little guide how I play Lux. This is my first guide so I hope this is not so bad. :D

-I like to go with lux some magic pen. with marks, so Lux have more magic dmg and thats good for her.

-I choose mana regen for seals. I think it's good for early game. Mana_regen is always good. :)

-I like to choose glyphs some cooldown, so Lux can fire her laser with lower cooldown.

-I take again some magic pen. for Quintessences. As I Said, Lux have more magic dmg and thats good.

My masteries is 9/0/21. I think cooldown is so great for Lux coz of her laser. Nothing more.

I like to start with Doran's ring. It helps you alot in early game. You have some hp and thats good. Some mana_regen and 15 ap already.

Then I like to go with boots. Lux is slow but not too slow when u start the game.

I just like mejai's soulstealer. Get it early, but if ur team is kinda noob or your team doesn't want to start / go in teambatlles or smthing like that u can get it later game or change other items like Archangel's staff.

Cooldown boots (Ionian boots of Lucidity). Why not magic pen boots? I like better for lux some cooldown. I think its much more better 'coz you have already some magic pen for runes.

Catalyst the protector is item. When you lvl up u gain 300 hp and 250 mana. So great!

Follow with Rod of ages. Good mana, hp and ap item. :)

Then you can choose Zhonya's Hourglass. 50 armor, pretty good and 100 ap. Thats good.

And last pick Rabadon's Deathcap. You can choose it earlier if you want. Great ap for lux. :Dd

Yeah, when ur lvl 1 you dont have good harassing spells. I like to start harrasing when I'm lvl 4-5. You just wing ur Lucent Singularity again and again and when ur lvl 6 and target is like 280 hp or lower u just fire ur lazooor up and he is dead. Thats my style. :D Ur lasor is so good ks spell, and I like to ks with it. I dont know why but its so fun. :) Have fun with it. When u are kinda low hp try to slow enemy first, then try to snare and use flash or ghost to get away. Nothing more to here. :p

I just pick to Lux ghost and flash.

Ghost - great escape tool or chase ur target down. If you see an enemy with low hp and you know ur laser will kill him u just use ur ghost and try to kill him.

Flash - So great spell. Kinda op :D You just jump over the wall with flash and ur safe (maybe >_>) You can chase ur enemy with flash too but not so great spell like ghost.

You can also think about ignite. Great spell with lux's passive but I just dont like take it with lux.

if you are wasting ur mana too fast and ur runes mana reg is too slow u can choose Clarity. Good support spell for others and you ofc. :D

Also Clairvoynce is good choise if ur afraid to waste ur ulti like me sometimes. :DD Nothing more to this guide. Hope you enjoy.