Lux,The Lady of Lurmonisty(If i spelled it right sup :D)
Lux is ranged AP mage which exceds at controling her lane.
She shines in teamfight,Needs utility and makes contact with other lanes.

I take magic penatration marks combinized with flat ability power glyphs and quintessences to improve my damage in early game.Cooldown reduction i desperatly need after reaching level 6.
Ill explain you that in next chapters.

I take ordinary caster masteries
9-0-21
Taking improved ability power and magic penatration in offense.
While focusing on cooldown reduction,movement speed,mana regen in utility.

Im trying to play Lux defensive offensive and full of utility.
Dorans Ring gives me health,ability power and mana regen which gives me all.
Soceress Shoes combinazed with my marks bring enemies magic resistances to 0.
In early game "sight".
Moonfair Spellblade gives me Tenacy and Ap for very low prize.
Rod of Ages is like Dorans Ring just that stats that it gives are incredibly bigger and instead mana regen it gives flat mana.
Zhryonas Hourglass is 3rd highet ap value item(After Rabadon Deathcap then Mejais Souulstealer)
Armmor isnt really what i need but i sure need its passive which will give me bonus utility in teamfights.
Rabadon Deatcap should be last item you get.
Combinized with my Ap ill be extremely powerful.

Light Binding is her main source of damage so i max it soon as posiblle followed by lucents sigularity taking my ultimate whenever availible and shield whenever point in other skills is unavailble.If you arent very skillshooter you should max your lucents sigularity soon as you can with light binding followed.

Ghost and Flash are great choises for Lux.
Since she has planty of disables that will allow her to escape and run away she has no movement abilities.So Flash and Ghost give her what she needs.
Teleport
Clarity
Ignite
also make great choises.

We discuses about item and rune build i use and about my spells.
In next few chapters we gonna discuss Luxes gameplay.

Something you need to know about Lux's combo is her passive Illumanation.
Since Ilumanation doesnt stacks you should allways land basic attack after 1 spell before using another.
This is my best combo:
Open up with light binding it will ensure your enemies wont escape your Lucents sigularity.
Land basic attack.Quickly hit E again to activate Lucents sigularty damage.Land basic attack.
Ignite the enemy in case you didnt take flash and ghost and you prefered ignite and teleport-flash-ghost-clarity.It doesnt really matter.
But it matters that your ultimate hits the target.If they are escaping in brush cover the brush area while moving ultimate on the side so they cant escape it.
If they are running down the river use your ghost to stay in vision and use the ultimate on the clift if they are going on to there.If they are escaping to other lane try to position it near the turret where you would usually recall.

Use Light binding over meele minions to farm and harras you enemies.
Lucent Singularity is great farming ability which is also good used for harrasing.
Since your enemy gonna be 90% ranged character he gonna sick to ranged minions.
Use your ultimate to deffend your tower.
Allways call M.I.A. :P
Here are champions that will except you in mid and they request diffriend gameplays:
Urgot:Escape him green bombs dunno how they are named duh.Do it becouse if they hit you he can harras you greatly fromt he range.
Annie:She has smaller range and you are enable to constatly harras her
Cassiopeia:This is every mid game players nightmare if Cassiopeia is skilled.
Allways remember that Miasma is growing poision so move atleast 5 steps away from it.
Noxious blast is hard to avoid but you can make task harder to harras you by moving alot in lane.Allways look back after position 1 spell of combo to avoid being stunned and being slowed instead.Move away if your poisioned becouse she can harras you with Twin Fang.
Twin fang has short range so it shouldnt be problem to move out of range since you get boots.
Fiddlesticks:Moonflair Spellblade gonna come extremely handy againist him.
Allways run from him after he drains you.When drain fades away bind him and place your combo to harars him.If you chooised ignite allways ignite him and harras him if he tries to drain cannon minion or any minion.
Malzahar:He has skillshots that are easy to avoid.Pay attention to effects.
Move out of Void call soon as you can even if it costd you flash.
You should use your skillshots from max range you got so his ultimate cant get you.
Aware if he has flash.If he does he can set down combo on you Easily.
Twisted Fate.Avoid 1 card but not agresivly.Moving too moch out of its range may get you in 1 of other 2 cards.
When he uses his ultimate wait about 3 seconds then bind him.
Vladimir:He is a beast!But he can be stoped very easily.Avoid getting aggroed by minions make sure he is only one that deals damage on you.That will get you in lead.However make sure he uses his transution on you before your light binding or lucents singularity.Becouse if he drains you after you damaged him his health will be re*****hed and your lowered.So when hes at full health he is not draining anything.Just dealing damage not repeneshing his health.
Also make sure he used Sangiune pool before using your ultimate as his Sanguine pool can make him lucker :D
Teemo:He is your biggest nightmare.Avoid harrasing him with Illumanation as he can blind you before you land it harras you while getting damaged only by a spell.
Lux itself:You should allways have your Light binding skillshot opened.You will see if she is trying to harras you or just to farm minions.
Try to play smart and not to stick near walls when low as she may put you in dieing edge.
Tristana:She probably will have smart gameplay.Harras you with explosive shot and standing back with her rocket jump. Allways react fast and bind her.If she tries to jump over you and pull you in turret you allways have flash.
LeBlanc:Make her busy with positon Etenal cains avoid being silenced and play with more care since she gets her ultimate becouse it is DEADLY.
Kennen:He is easy target to you,before lvl 6 stay behind your minions so you dont get harrased by shuriken and beware after he used his 4 basic attacks ashe may harras you with it(it will have signifact bonus damage) add you mark of storm and he will be enables toharras you with her E.At level 6 he will use his Lighitng rush to get in range of you and kill you with ultimate,stop it by binding him when he uses lighting rush and running back.
Caitlyn:Stay behind you caster minions BEHIND not near to lower her damage from piltover peacemaker.However if you can avoid it no needs to stay behind. Dont allow her to get you over thin walls with her peacemaker allways try to stay out of posible range of its like near by wall that is on other side of her.If shes on left go on right part of wall and if shes right go on left side where is a wall but allways move foward in meanwhile.Flash+Ghost our of her range from Ace in the hole.However if she has Claviyorance dont use your summoner spells try to shield yourself and hope for the best.When she cahrges her headshot stay back before she uses it on minion.
Ryze:Stay back when he uses his bouncing thing so you dont get bounced.Dont go agresive on him in small range he can bind you then and set his full combo.
Sivir:Avoid boomerang blades.
Orianna:Harras her once she loses the ball.
Katarina:Flash away when she shumpos you then bind her.
Anivia:Avoid flash frost dont be near so she can ulti you and set skillshiots.Flash over frost walls if she is problematic.
Karma:Allways do your full combo on her when harasing as she may just heal herself while farming.Allways stay in long range so she can harrras you with Heavenly wave as its her main source of damage.If she uses Spirit bond to help her bind her and move away
Vayne:Stay away from walls and stay in center of lane.Bind is her most horrying nightmare as she cant tumble.
Zilean:Bind him once he tries to get in your range for time bomb using his movement thingy.
Janna:Pay attention on sounds of tornado.Allways stay back againist her since she is fast and can harras you ot like other champions.
Veigar:Avoid getting stunned,Avoid meteors.Harras him all the time so he cantt farm with Balniful Strike
Soraka:Stay out of Strallcall range and harras her so she cant attemp to you and silence.
Ashe:Stay behind creeps so she cant harras you with volley and warn your allies in what direction arrow is going.
Ezreal:Same like with Ashe.Stay behind minions so he cant harras you with mytstic shot and warn your allies in what direction his barrage is going.
Kogmaw:Avoid his ultimate.Get out of slow area fast.When he tries to use his skill which gives him range bind him and stay back till its off.
Brand:Avoid his Sear and Pillar of Flame to minimaze his OP damage. If he ultimates you dont walk in turret as your minions may be near and kill you instead of helping you out.
IF SOMEHOW Sona goes in mid:Allways stay back out of her basic attack range when she has Power Chord activated.Bind her if she is running towards you after lvl 6 as maybe she wants to stun you.

Allways stay back.Harras their tank but not agresivly! Position yourself so he is 2nd target of your bind so you damage more important target and making the tank less availible to tank.Allways be poitioning your ultimate where it hits most enemies.

If you meed extra cash use ulti on ghoul camp and go to base.Your ulti is on low cd so dont be afraid though!

Well i dont know what you think but i find this as solid build for me :)Hope you like it.
Next build i will create is Killer Sona.
See yah :)