This is my Lux guide, quite simple, good amount of AP, and almost full cooldown redcution. This allows for maximum slapping power. With these bad boys items, nothing will stop you from becoming legendary! This build is for maximum lazer fire. Lux's range mixed with her damage makes her an amazing middle, countering many champions.

The runes are your basic Ability Power Carry runes, mana regen, magic pen, and ability power per level, with flat ability power for the Quints. This allows for good sustain, while not giving up much damage, and it helpts you get through the earlier magic resistance.

The masteries are the same thing, basic Ability Power Carry, 21/0/9, 21 for damage, 9 for movement speed, mana, and buff extension.

The reason I start with my E is because it has good range, good damage, and AOE plus a slow. The reason I max out E, is because of the slowing effect increasing per rank. W is next because it is good for a shield to be high, as you don't have much health with this build. The snare does not increase per rank, only the damage, so it's not that important. Lazer as soon as you can rank it up.

Summoner spells are once again classic Ability Power Carry choices. You may also use Clairty, teleport, or something else, just for laning phase and what not. I use Ignite to secure kills early game, stop heals, and just damage over time. Even though I had Morello's Evil Tome, it is easier to use Ignite, then that unique acitve, because the numbers are a bit out of the way in my usual combos. My other choices would probably be Ghost, Clarity, Heal or Teleport, depending on the enemy team.

To summarize it all up, I basically go for Cooldown Reduction, a good amount of ability power, mana sustainment, and high bursts, your E should be doing around 1/5 to 1/4 of the average non carry health, discluding tanks. The build is decently strong early game, allowing for a spam from the regen of Chalice of Harmony, with good ability power, magic resistance too. You're not that tanky, but who needs health or armour when the ad carry is dead in 3 seconds anyways!