Hi guys, this is my first build so yea...
This build makes sure you can nuke down most champs and is very game changing!
This build is just ripping through your opponents magic pen.
please comment and tell me how well it works!
-Thx

btw-if you see me, ill probably nuke you down with this build

Most runes are in magic pen. as that is what the build is for.
The Greater Seal of Resilience are for armor since there are no magic pen. >.<

I have 9 in Offense as you should get magic pen. by 15%. its a plus!
i have 2 left over so i place them in defense, doesnt matter where you place them...
19 in utility as this is manly the ap champs masteries. just get mana regen and cooldowns and movement speed (it helps)

i start with an amplifying tone and a health pot. that should last until you have enough money to buy the haunting guise. i buy the sorcerers boots. sorcerers boots and haunting guise gives you 40 magic pen. which is a lot in the early game and is still is since late, most carry champs won't be buying any magic resist at all. after this i usually go for a lich bane. i feel like this is a good early game item. you are gonna have high ap so lich bane works wonders! late game, you can choose to sell it or not since its not that useful, but i tend to keep it cause it gives you the extra movement boost which could let you escape or get you a kill. as any ap champ (well maybe not ryze... but i havent seen a build of him), you should get the rabadons deathcap. not more to say. i get an archangel staff after. more mana regen so you can stay in the fight longer. your last item really is up to you: more health or damage output. for a health item, you could just buy almost anything. for more damage output, i would buy a second archangel staff. more mana means more ap! ^^

i usually start off with light binding first. this skill usually is used the most and does a lot of damage so i max this skill first. at lvl 2, i lvl up prismatic barrier. this move helps allies survive. i max this skill second. at lvl 4, i get lucent singularity. this is mostly a minion farming move. you only need this for the slow. instead of maxing out light binding, you could max out lucent singularity if you are aiming for minion kills. MAX out your ultimate as fast as you can. at lvl 3, it has a cooldown of 36 or so seconds.

my first skill is teleport. this lets me recall back and rejoin the fight much faster so i can make up for lost exp. my second is clarity. i sometimes find myself out of mana really fast.

*flash is a good choice as well but i don't like it cause i can't escape turret shots no more. >.<
*ghost is something to look at. good overall

get blue buff a lot. why? no, its not for the massive mana regen. its for cooldown!
with the cooldown, your ultimate only has around 26 sec to cooldown. also with the magic pen. you will be shooting at least a 800+ nuke to the enemies carry every 26 or so seconds!

Pros:
-massive damage early and late game
-force enemies carries to run (or kill them) and leave only tanks
-800+ nuke, who doesn't want that?
-really easy to use

Cons:
-must master prismatic barrier!
-no way of living (except lich bane for movement speed)
-run in, nuke, run away like a ***** (repeat process until enemies are dead or you are)

Lux is a skill shot champ so hitting the light binding is critical.
prismatic barrier can mean life or death! it makes against teemo's annoying shrooms! trust me, it saved me many times... XD
Lux's ultimate could turn the tide in battle since it hits a pretty huge area. Aim it well, you might not get another shot!