Welcome to one of hopefully many Orianna guides you will encounter here on mobafire. It is probably of no surprise when I say this is my first guide. Let's get to it!

Orianna is a utility heavy character whose Ball is a vital extension of herself. She has good versatility for damage, harass, support, and CC. More often than not, Orianna works better with another teammate.

I think Doctor Awesomer states Orianna best:
"There are several key things to consider when thinking about Orianna's damage.

First off, consider Orianna's range. It's very long, obviously, for good reason: Orianna is a rather fragile champion. What she lacks in fortitude, she must compensate for with distance and deceit. However, even in her range, she has limitations--though her power is very great on enemies near The Ball, she is largely powerless against enemies outside her sphere of influence (pun fully intended, but it's a good way to think about her spells.) She can only move The Ball so fast, and only so often--if she leaves too wide a gap in her defenses, the tide of battle could turn against her very quickly.

Most other casters are, ironically, less constrained with their spells; if Brand misses one of his spells, he doesn't necessarily miss his others, but Orianna's maximum burst requires her to go "all-in"--if your Q is off its mark, your W, E, and R are rather unlikely to hit anyone, and now you're fairly vulnerable. Hopefully, this is when the player starts thinking: perhaps there's a better way to approach this situation?

The challenge of playing Orianna comes from knowing that you can only do so much from one position, and you can only change position so fast, and then planning how you will move your sphere of influence through the battle, several moves in advance. If you move the ball here, where can you move it after that? Where will you need to move it after that? Who will you need to defend, and who can assist you in attacking?

There are lots of little bits and pieces that make these decisions quite interesting. My favorite is the haste bonus on the W; sometimes, you might be more effective not even using it to burst, but instead hasting your whole team, particularly an initiator holding The Ball (anyone tried putting The Ball on Rammus yet? He seems to think it's pretty okay. ) Perhaps it's best to poke exclusively with Q, saving the W to punish and escape melees when they dive for you after you've recalled The Ball with E.

Her passive is a similarly interesting tradeoff--you have to get much closer to use it, but it offers very reliable damage compared to The Ball, and being closer means The Ball will generally hit targets easier since it has to fly less distance from you, but of course you've now given up the safety of range. It's a great reward for the tactical Orianna player who can spot those openings when it's safe to close and get some extra damage in.

In any case, the goal is always to make a champion feel rewarding to play well, and maximum burst is one way she can be very rewarding--the key is to remember it's not the only way, and it's not even always the best way."
http://www.leagueoflegends.com/board/showthread.php?p=9511686#post9511686

As always, you do not have to follow all of the items, runes, masteries, or the skill sequence. These are purely the standard I follow but are capable of being changed based off fellow and enemy champions as well as the current situation. Continue down reading for more information on various situations and alternatives for items.

Pros:
Good overall utility
Nice laning phase with use of Q
Decent farmer especially later game utilizing Q, W, and E
Movement speed increase/decrease ability
Shield that can also grant Armor/Magic Defense
Can cancel enemy channeling with her own ultimate
Passive can become potentially stronger later game
"Capable" of carrying


Cons:
Requires synergy with her unique play style, quite difficult
Squishy especially without her ball
Mana intensive early on
Her AP ratios are fairly low
An understanding that protecting teammates > getting kills (a common problem among Orianna players who focus on damage and forget their teammates)

More on this in the Laning and Strategy and Tips sections.


Clockwork Windup
(Innate): Orianna’s autoattack deal additional 5/10/15/20/25/30 (+0.2 per ability power) magic damage every hit, subsequent attacks on the same target within a few seconds will add 15% more damage per hit. This bonus stacks up to three times.

Quite underrated, this passive gets potentially stronger later in the game. The wording can also be a bit confusing. Let's use an example.
If you have 502 AP, your bonus damage will be listed as 101.16 on the first hit. The second, third, and fourth hits will deal 101.16+(15/30/45% of 101.16). So on the fourth attack, you would be dealing (101.16+(45% of 101.16))=146.68 damage.
Many of my kills have come from finishing people off with melee attacks whenever my abilities are on CD.


Command: Attack
(Active): Orianna commands her ball to fly towards target location, dealing damage to targets hit but doing reduced damage for each additional target hit. Her ball remains behind at that location afterwards.

Your main skill to max out for damage and CD. This skill will be great for poking in the lane and clearing minions after Catalyst the Protector and Rod of Ages in conjunction with your other abilities.


Command: Dissonance
(Active): Orianna commands her ball to emit a magnetic pulse, dealing damage to units around it. Afterwards, the ball leaves a field behind for a few seconds that speeds up allies and slows enemies.

The second skill to max. An ability that can slow enemy champions but also speed up ally champions? Heck yes! Let's not forget the damage it can do as well when you get your Rod of Ages. However, be cautious with using this early on as it will drain your mana quickly and won't do as much as your Command: Attack which is your main source of early damage.

Command: Protect
(Passive): The allied champion the ball is attached to gains bonus armor and magic resistance.
(Active): Orianna commands her ball to fly to and attach onto an allied champion, dealing damage to enemies it passes through and shielding the allied champion when it arrives.

This can save lives more than you'd believe. Not only does it give a shield, it adds armor and magic defense to the attached champion. If someone is being focused, be sure to throw this on and add a Command: Dissonance if they are retreating/tower dived. Couldn't tell you how many times this has saved people even from just Ignite or Requiem.

Command: Shockwave
(Active): Orianna commands her ball to emit a shockwave after a short delay, flinging affected enemies in the vicinity into the air a set distance towards, and possibly over, her ball.

An underrated skill. Most Orianna's you will see won't use this properly. Do not use this purely for damage. Save it for preventing an escape or stopping certain ultimates such as Death Lotus, Absolute Zero, Idol of Durand, Nether Grasp, Infinite Duress, and others that require channeling. Can even be used to stop a tower dive if you've blown through the other skills.

These runes are fairly typical for AP champions, you can substitute for your needs and availability

9x Greater Mark of Insight (Magic Penetration, nothing unusual here)
9x Greater Seal of Clarity (Orianna's skills can cost quite a bit)
9x Greater Glyph of Focus (CDR is important to allow maximum use of her skills especially Q)
3x Greater Quintessence of Fortitude (I can not express how many times I have survived on all champions because of these)

Mix and match as you please to your tastes, I know some would prefer ability power Glyphs for example or movement speed Quints. I found the above to work best for me.

9/0/21

Nothing unusual here.

Offense:
Sorcery
For CDR

Archaic Knowledge
For Magic Penetration.

Utility:
Good Hands
Incredibly useful late game if you are unfortunate to fall in battle. That 10% may seem small but the longer the game is, the bigger this % really helps. I am sure there have been times where if you spawned just a second earlier you could've saved a tower/inhibitor/nexus.

Haste
Stronger ghost with your W and Quickness can mean the difference between survival and getting a kill

Awareness
For that EXP to get ahead when possible of your opponent (or on level if they too have it).

Meditation
Because Mana Regeneration is vital for Orianna's skill costs.

Utility Mastery
The single point in this can benefit the times you may obtain blue unless you have certain champions like Swain Anivia or Kog'Maw on your team who need it more. Either way, you may get it from enemy champion kills.

Quickness
Combined with your W can break the distance between you and your opponent.

Blink of an Eye
CD on Flash is always great to have coupled with Presence of the Master

Intelligence
More CDR for Orianna's skills

Presence of the Master
Having Ghost and Flash CDR as low as possible is a great welcome

Why no Perseverance? I link you to here explaining why
http://www.leagueoflegends.com/board/showthread.php?t=219077
Link provided by EvilDice's Singed fantastic guide

Flash


Ghost


Orianna is flimsy if targeted and if W isn't enough, you may require that extra oomph with Flash or even Ghost.

Teleport


A fair alternative if you lack a pusher on a team or saving a tower.

Items items items

Do not believe the above item list needs to be in that order and those specific items. There will be circumstances you can adjust based on your needs and both sides champions.

Let's however start with why and when to use the above list.

Core Items

What, only two core items? Orianna is versatile and will require items based off the champions and situation on both teams. More on that below.


"We go."
I usually start with these so I can build into Catalyst the Protector faster for better and longer laning. You can choose Doran's Ring if you feel that you may be outharassed.


"Protect."
Catalyst the Protector This will keep you in the lane longer for health and mana. Alternatively, you can choose to build a Tear of the Goddess but I found the difference between getting Rod of Ages earlier for the Health, AP, and Mana to be more beneficial and put you ahead of the opponent's Orianna, who would otherwise only have more Mana Regen than you and nothing more.


"Why are they running?"
No explanation necessary. I try to get this with Catalyst the Protector if possible.


"I have sharp things."
Your first completed core item. This little darling will give you a whooping (when maxed) 80 AP, 630 Health, 725 Mana, a significant boost to your power and survivbility. Let's not forget that a recent patch has allowed Rod of Ages to keep the Catalyst the Protector passive ability to restore Health and Mana when leveling!


"We are as one."
Your second and last core item. You may be wondering why I didn't pick Sorcerer's Boots. Well, I found CDR to be more important to stack for her abilities such as her Q to get as low as possible for poking. More information on that in the CDR section below.


Now we have a couple choices to make.


"Yes, I am a weapon."
If you are unsure what to choose from, grab this for more AP.


"Why do they keep breaking?"
Typical choice when enemy champions stack magic resist gear like Force of Nature and Banshee's Veil. Recommended for late game as well.


"I hear soft things."
Too much CC on the enemy team? Grab this and get back into the fight.


"Time tick-ticks away..."
More AP late game after Void Staff if you are unsure what to get or if the enemy team is mostly AD. The passive active can help avoid being focused.


"When you fall, you get right back up."
An interesting item that I have tested on and off if my team was mostly AP and ability heavy. You can get this earlier if your team is winning especially if you are fed. The replay matches I will post can show its situational use.

"Ravage"
Another possible item to incorporate with your Clockwork Windup for big damage late game.

Orianna is capable of going mid but would be better off laning with a partner.


Early Game

Because of her Q Command: Attack she can keep most champions on their toes. Leaving her Q out behind the minions and near the enemy champions allows you to harass with it by moving it towards them over and over. By keeping it behind the minions, it forces the enemy to be more cautious as they'll take the full damage from Q as opposed to the reduced from hitting multiple minions. Save your W as it will be fairly weak early on and cost more mana than your Q except when going for a kill with your partner.

Be weary however of certain champions such as Caitlyn whose range will be your demise. Be sure your laning partner is capable of handling such long range champions or ask to switch lanes with another.


Mid Game laning

If the laning phase has lasted this long, you should have gotten your W Command: Dissonance to level 2 or 3 and have Catalyst the Protector with Boots. If by chance you have done well and have a Rod of Ages, you'll be able to push that tower fairly well with good harassing power from both Q and W. Do not forget your passive's power even with little to no AP during cooldowns as it adds up.

As always with laning especially by this point, you should be having a Sight Ward set up at the river to avoid ganks.

Some people may look at Orianna's abilities and their low cooldown wondering why you would ever need CDR.

When it comes to fights especially team fights, you want to exhaust your abilities and be able to use them quickly again.

Let's do some math with this.

With the Greater Glyph of Cooldown Reduction, Masteries, and Boots of Lucidity, we hit the 30% CDR.

Command: Attack at level 5 becomes 4 seconds.
30% CDR will put this at 2.8 seconds.

Command: Dissonance at level 5 becomes 9 seconds.
30% CDR will put this at 6.3 seconds.

Command: Protect at level 5 becomes 9 seconds.
30% CDR will put this at 6.3 seconds.

Command: Shockwave at level 3 becomes 90 seconds.
30% CDR will put this at 63 seconds.


While we look at the CDR we see how it affects the ultimate more than the others, however it is still incredibly helpful with each of the skills.
Every second counts with having the ball flung at enemies when chasing and team fights.

The ball is an extension of Orianna's body and her main weapon. She requires to throw out all her abilities mid and late game to save allies and slay enemies. This can not be stressed enough. It is like building attack speed on your AS champions like AD Twisted Fate, you want to keep attacking during fights as much as possible!

Positioning of the Ball is VITAL!

Take advantage of your Q Command: Attack

1) As mentioned in the laning section, keep your Q behind minions and poke with the enemy with it. While it may not seem much damage early on, it will add up and keep them overly cautious of you.

2) Remember where your Ball is during team fights. If it is not near you or the enemy and you attempt to Q, it will take longer for it to travel thus missing potential kills or escape (such as hitting W only to realize your Ball wasn't where you thought it was)

3) Harass the heck out of your opponents at their tower with Q. They will be forced to back off more allowing possible hits on the tower by you or allies.

4) Q reveals bushes and behind walls, use that to your advantage.


Having W Command: Dissonance is very versatile!

1) Employing Q and E, you will have control of ally and enemy speeds. The cooldown is longer than Q so make wise choices with this and not use it prematurely for damage.

2) You can use this on yourself by just pressing W. Very useful for returning to lanes or escaping ganks as the enemy will have to walk over it if they are chasing. Throw in an E for extra protection.


Use E Command: Protect for saving lives and further harassing!

1) When an ally is being targeted and not the tank, such as your carry, throw this on your teammate to give them the shield and armor/magic defense especially if you know when something can kill an ally or yourself by anticipating it. Examples can include Requiem, Ignite, Finales Funkeln, and many more.

2) Let's say your team is chasing an enemy and you are too far to use Q --> W to slow them down. While you could W yourself and catch up, it would be better to use E on the ally ahead of you and boost them with W. Chances are, they are more likely to catch them than you will. Can throw out your R Command: Shockwave while it is attached to your ally.

3) E can also do damage during it's travel, this is a bit hard to control like Karma and her Spirit Bond. A possible combo can be Q --> W --> R --> E (providing R didn't throw them past the Ball's travel for E). Remember that E can attach to yourself for that combo to work. This may also be used in farming though simply throwing out Q and W would generally be enough.


And R Command: Shockwave as the show stopper

1) Just like with W, make educated choices when using this ability. Use it in conjunction with Q --> W if they are trying to escape. May also be used with E if attached to an ally ahead of you if necessary.

2) Can be used as a tower dive initiator giving enough time to jump the enemy with your allies.

3) Cancels channels as stated before like Death Lotus, Absolute Zero, Idol of Durand, Nether Grasp, Infinite Duress and others.


Never neglect your passive Clockwork Windup

1) Always be sure to melee when viable as you use your abilities even during cooldowns. The damage on this can mean the difference between a fallen enemy or a a grateful escaped one. I can not stress how many times I have finished off people at the last second with melee during cooldowns on Orianna's abilities.

2) The more AP you have, the more dangerous this becomes. 503 AP equates to 101.16 on the first hit and 146.65 on the third.


More to come and with videos soon!

Coming soon when LoL Replay cooperates

Fellow summoners I play with whose great teamwork allowed me to explore Orianna's capabilities.

Winstonton and Jewlius for giving me replays of our matches when I forget to open LoL Replay. Check out Winstonton's AP Shaco guide here.

Phreak for some of the tactics in the champion spotlight video.

And Riot, for creating one of my favorite champions to date!