There once was a Piltovian man named Corin Reveck who had a daughter named Orianna, whom he loved more than anything else in the world. Though Orianna had incredible talent for dancing, she was deeply fascinated by the champions of the League of Legends. This fascination compelled her to begin training to become such a champion. It is unfortunate that her sheltered, wide-eyed naivete led her to take unnecessary and dangerous chances which ultimately led to her tragic demise. Orianna's death shattered Corin, driving him into deep depression and an obsession with techmaturgy. He could not stand the void his daughter's death left in his life, so he decided to build a replacement - one that would complete Orianna's dream of joining the League. What was created is the clockwork killing machine that Corin named after his daughter. Knowing that she was destined to be a champion and seeing the way the times were changing, he created The Ball as her pet and protector. This nearly symbiotic creation uses a different type of techmaturgy, relying more heavily on electricity than clockwork.

Orianna and The Ball now fight as Champions in the League of Legends, using her sometimes misguided morality as a compass. She tries in earnest to fit in with those around her. However, no matter how hard she tries, Orianna can never be human and there is always something unnerving and alien about her. Though she attempts social interaction with other champions in the League of Legends, there are few who can get past her exotic nature. To many, it's as if there's nothing inside, that Orianna is just a soulless clockwork shell - a dangerous and deadly one at that. However, all along she remains the perfect daughter in her father's eyes.

''Dance with me, my pet. Dance with me into oblivion.''

Orianna is known as a mid AP Champion, i will explain in this guide why she should be known as one of the best Support champions in Game.

To show you that Orianna is a full support i will compare her with a commom Support like Janna:
Janna is known as one of the best Supports because of her Eye of the Storm Shield, Zephyr slow, and cc. Orianna have the same. The Command: Protect Shield absorbes the same damage (80/120/160/200/240) Jannas shield gives additional damage as long the shield is not brocken. Orianna's ball gives additional armor and magic resist as long the ball is on the champion. This means your AD Carry have armor and MR (10/15/20/25/30)all the time in lane for free. Also the cooldown for the shield on Orianna is shorter(10 sec vs 9 sec), the range is higher (995 vs 800) and the mana cost is lower (60 vs 70/80/90/100/110). You wont have any mana problems with orianna Support!
The Zephyr slow from Janna is just a bit stronger than the Command: Dissonance slow from Orianna (24/30/36/42/48% vs 20/25/30/35/40%) but Orianna's spell can also speed up friendly champs (most of the time used while the ball is on your carry to help him chase down the enemy) and is an Aoe Spell.
At least place your ball whisly for your ult, it's a skill shot, but with a few games training you will be able to pull back enemies, safe your teammates from enemies or interrupt other enemy cc-ults (like Galio, Kata etc.) So its kind of the same stuff what Janna is doing with her ult. Dont fogett that your ball is doing damage everytime the ball fly to an other point.

Because you will face AD Carries in botlane, your runes should be focused on armor. I pick also a few mana reg and of course gold per 10 Quintessence. = High Sustain in lane and a lot of extra gold for wards. Allways buy wards!!!

Start with Faerie Charm + 2 Sight Ward + 1 Vision Ward. If you like to skill extra start gold in your masteries you could get some health pots too. But usually i dont need it.
Go for an early Philosopher's Stone! Go back to base if you reach 620 Gold or + 75 for additional ward.
Next item is Heart of Gold, you need 825 Gold before you go back, I recommend to wait for at least 1175 Gold to purchase Boots too. This is your core build.

Later you go for Shurelya's Battlesong and Randuin's Omen. But keep in mind that you loose the passive of extra gold if you complete these items. Complete your shoes normaly to Ionian Boots of Lucidity. But allways watch your enemies before you decide which boots you buy.
In 90% of the games you won't be able to finish Zeke's Herald or Rylai's Crystal Scepter, because the game will end.

Dont forget to buy wards! Watch the enemie Support to counter wards. You allways have to know how many wards the enemie support has.

Flash for escape! I cant live without.
I will explain why I prefer Clairvoyance over other summoners:
CV the enemie base after about 10 sec you and your teammates have an advantage if they know how the laneing enemy start. Not only CV their base, watch if they walk away in a group, this could mean they will invade your jungle, warn your teammates. Watch how many wards the enemie supporter buy. Dont spam your CV when its up, use it whise. Watch your top lane if your teammate is pushing without ward help him with CV not to get ganked. If your jungler tries to gank - your lane or other lanes - have an eye on it, you could help by using cv in bush when the enemie tries to escape via a bush. (I blame riot for not giving assists for CV) This could also be used later in teamfights or when chasing an enemie, allways be sure your carrys have sight to the enemie. Dont forgett, you should also use CV in your own lane.

Q - Command: Attack - Orianna commands her ball to fire toward a target location, dealing magic damage to targets along the way (deals less damage to subsequent targets). Her ball remains at the target location after.
Orianna commands her ball to shoot toward a target location, dealing 60/100/140/180/220 (+0.6) magic damage to targets along the way. However, it deals 10% less damage for each unit it hits (Minimum 40%).

Her ball remains behind at the target location afterwards.
Cost
50 Mana
Range
815

W - Command: Dissonance - Orianna commands the ball to release a pulse of energy, dealing magic damage around it. This leaves a field behind that speeds up allies and slows enemies.
Orianna commands her ball to release an electric pulse, dealing 70/115/160/205/250 (+0.5) magic damage to nearby enemies.

The pulse leaves behind an energy field for 3 seconds, lowering enemy Movement Speed by 20/25/30/35/40% and increasing ally Movement Speed by 20/25/30/35/40% for 2 seconds. This effect diminishes over time.
Cost
70/80/90/100/110 Mana
Range
255

E - Command: Protect - Orianna commands her ball to attach to an allied champion, shielding them and dealing magic damage to any enemies it passes through on the way. Additionally, the ball grants additional Armor and Magic Resist to the champion it is attached to.
Passive: The ball adds 10/15/20/25/30 Armor and Magic Resist to the allied champion it is attached to.

Active: Orianna commands her ball to travel to and attach onto an allied champion, shielding them for 4 seconds from the next 80/120/160/200/240 (+0.4) damage. Enemies the ball passes through along the way are damaged for 75% of the shield value: 60/90/120/150/180 (+0.3).
Cost
60 Mana
Range
995

R- Command: Shockwave - Orianna commands her ball to unleash a shockwave, dealing magic damage and launching nearby enemies towards the ball after a short delay.
Orianna commands her ball to unleash a shockwave after a brief delay, dealing 150/225/300 (+0.7) magic damage to nearby enemies and flinging them into the air a set distance in the direction of the ball.
Cost
100/125/150 Mana
Range
410

Passiv: Clockwork Windup - Orianna's autoattack deals additional magic damage. This damage increases the more Orianna attacks the same target

Stop farming. Seriously, dont attack creeps as long your carry is on your side.

Make sure you stay behind, you are ranged.
Prepare when your tank is initiating a teamfight. For example if Malphite initiate with Unstoppable Force place your ball on him and activate your ult Command: Shockwave directly after malphs ult. This also works with Galio, Amumu, Alistar, Sejuani, Hecarim etc.
Place your ball on your carries for shield, armor, magic resist and if nessasary extra movementspeed.
Dont plink the ball around with Command: Attack you dont make a lot of damage.