I like Lux a bit, and my friend just started playing LOL and plays her so I thought I'd build a guide. Ps my first guide and not too detailed.

For both lanes You want to level your q first just for the sake of being able to escape an early gank or laying on some damage early. After this it varies. On mid always max out e as soon as you can, but as the support it depends on your adc. If the ADC seems to be good then you can level your e and go for a kill lane, but if he gets in trouble or you find him having bad positioning you may want to focus leveling your w.

Runes are the same either way. AP = damage.

Support Masteries obviously want to change for the support role into a more diverse setup, mana regen gold per 5 and extra ward help quite a bit early game if you know how to use them.
Extra gold. Try to auto attack the enemy champs as much as possible for Gold. this mastery setup also gives you an extra potion at the beginning due to the +40 gold, plus the 1 minute ward.

The one minute ward: place it at around 2:00 minutes.(if you are blue team) if they dont gank by 3 minutes it will probably be safe to wait until around 4 min 30 sec to use the normal ward you bought. If you're purple team, you can expect a gank after the jungler does red. Since they usually start blue this should be around 3:30 so make sure your normal ward is there in place before that. In this case the one mite ward can be used in tri bush or the bushes near the wall if the enemy is hassling you from them. *** if they have a jungler that can start red or you notice bot lane is missing right off the bat, then go place your one minute ward in river immediately and expect that early gank.

This Mid build gives you 24 sec Ult CD and lots of mana. Sit outside base and poke away with High Damage. Same thing for Support build but some more early gold and longer until you can Pwn people. plus wards are needed so buy them often.

Mid:
Kages gives you some early Gold. If you find yourself home with 1600 build at 1st back skip the build and get Rabadons first, if not go through the build order. If you find yourself behind then you can go with Skipping Rabadons until late. the only trick in this is not to buy two Fiendish Codex at the same time. Unique Passives that don't stack.

Top:Same Basic build! Rabadons definitely last though. Probably wont make it too it. Also buy lots of Sight Wards, or if you want you can get A sightstone before finishing boots.

I personally choose Teleport over the traditional ignite. a wild lux appears.....Shield to save yur teammate q to snare and ult to finish them off can turn an enemy gank into a suicide and even pick up a double. use it wisely you only get it once every few minutes. Also if you cant get the enemy running away with your ult than you have some issues, no need for ignite. Time your combo for the right amount of damage. and use your passive.

High damage and Low Cool Downs. Great team help with shields well places. Ult gets enemies who are running away, and a cc snare/slow combo.

Weak against anyone who is highly mobile, like kass, diana fizz kat or akali. they all murder you.
Squishy.
shes not hot :(