Lux has been my main for a long time now even though I play a wide range of characters. I've recently begun playing her again and really like a this new build I've been using so I thought I would share it. This build allows you to deal good damage and if you are able to get kills early, carry the team. This build also allows you to play a more support role if you don't do so well early. One thing you can do to make Lux a little easier to play is mastering smartcast. I cannot stress how important this is when playing Lux. You will find yourself landing many more light bindings and with Lux that normally makes the difference of whether you win the fight or not. I have just set my Q button to smart cast and use it with all characters because it is so useful. You may want to play a few games without it to get a feel for how long the range is but when you do you'll want to use smartcast as much as you can.

These runes are my standard caster runes. I don't believe in changing runes every time I play so they are pretty basic. =P You could get more creative and use flat AP Quints which will help you early or CDR blues because CDR is so important for Lux. There's definitely some flexibility with your runes but if you go with these you be fine.

Standard caster 9/0/21. I take improved Ghost, Flash, and Clairvoyance because once again I'm lazy and don't like changing my masteries if I choose to take Ghost/Flash instead.

Mejai's

I think its pretty important to rush Mejai's on Lux. This is what allows Lux to carry a game so its pretty important to get it early. Lux is also pretty good at getting assists later in the game so if you don't do well early don't worry, you should still be able to make it worth the purchase.

Ionian Boots of Lucidity

Lux NEEDS CDR so bad. Her spells are amazingly powerful but have fairly long cooldowns so these are the best boots for her in my opinion. Sorc Boots are an option but this build gets enough magic pen with runes, masteries, and Void Staff that I don't think you need them.

Lichbane

This is a great fit for Lux because it gives you a little bit of everything. Get it early for the movement speed and extra damage proc.

Rabadon's Deathcap

This is just the biggest boost in AP you can get and needed if you want to deal decent damage later into the game.

Void Staff

Now that you have your AP up get this to help you push past some of that MR that enemies will have by this time in the game.

Deathfire Grasp

This last slot is pretty flexible. I grab Deathfire Grasp because it allows me to burst someone down in team fights. You could go with a Zhonya's Hourglass here too but what I find is that if you are forced to use the invulnerability you are most likely going to die anyway.

You want your best CC ability at level one in case you need to fight and then level you want to max lucent singularity next but I normally take a point in shield at lvl 4. Next you want to max light binding to get your damage up during mid game and finally max shield last. Prismatic Barrier is a great skill but you really don't need it till late when lots of team fights are happening. If you are doing poorly early you can max shield second if you feel like you need more support but I have found that the CDR on your Q is too important.

I love Flash/Clair on Lux. Flash is pretty necessary on any caster and clairvoyance synergizes so well with her ult. Clairvoyance can really change the way the other team has to play and allows you to play more aggressively by knowing if a gank is coming and also puts some pressure on the enemy jungler. This is also another way you can support your team if you find yourself without kills early in the game. You can always just use Ghost/Flash if you feel more comfrtable but at least try out clairvoyance first, it is very underrated.

I really enjoy using this build because it allows for a few different playstyles and lets you still be able to contribute to the team even if you aren't doing well. If you've never played Lux before you should at least give her a try with this build and see if you like it because she is extremely fun to play. She is a champion that can be very rewarding because of all her skillshots. If you already play Lux switch to my build for a few games and see if your scores improve at all.

I hope to add some more to this guide with some in-depth tips and strategies on how I play her in the near future so check back.

Feedback is welcome. Let me know what works for you and why.