Orianna is an unique champion that uses "The Ball" as the focal point for all her skills unlike other champions whose skills comes from themselves. This ability gives Orianna a different play-style as you have to control two different entities together in order to make the most out of her abilities.

Orianna can "poke" enemies, using her huge range, she can deal damage to enemies at a great distance who cannot fight back unless they commit to the team fight. She can deal damage to the enemy from a distance away, and offers a good amount of utility to your team in the form of slows, hastes, shields, an AoE disable and she can also send The Ball to scout brush or over walls as it provides sight.

She has a high learning curve, but is very fun to play and brings useful skills to your team.

Provides magic penetration, great all throughout the game.
No other mark offers as much.


Not much mana regen is in this build, and you won't always have blue buff.
These will keep your mana pool healthy.


CDR is great on Orianna, allowing her to slow, haste, shield, and cast her ultimate more often.
Focus for early game offense, Celerity for a slightly better boost late game.
All preference here.


See marks of insight for reason.
Speed quints are debatable, it'll help Orianna go in and out of battle with Lich Bane better, but I feel like the boost is rather unnoticeable. Your choice.

Not much to be said here.
Pretty standard caster, 9/0/21.

The only slight divergence is that I take 1 point in Perseverance and 3 points in Good Hands.
The reason for this is that 1 point in Perseverance gives you 2% bonus regen, but the next 2 points gives only 1% per, so I find the decreased death timer more useful. Ideally you won't die, but things happen.


You can take a point in Greed if you want, but Orianna can farm pretty well, so gold shouldn't be that much of a problem. God forbid you play full support Orianna when there's champions like Janna and Zilean.

Start with:

This gives you plenty of mana and health regen to stay in lane until you get the 1150 gold required for your Philosopher's Stone and level 1 Boots. At which point you should use your Q W E combo and auto attacks to clear a wave and go buy. If you're in a duo lane, just tell your teammate to stay safe.


First trip:
Philosopher's Stone Sight Ward
You'll want your Philosopher's Stone early on to reap the most benefit from its effect, and you need boots. Why? Because your opponents will get boots. Being faster lets you chase down enemies, run from ganks, travel faster, or just run when you realized you screwed up. Wards pay for themselves, even if you don't realize it. They keep you safe from gankers, which'll allow you the safety to push up a bit further to get those last hits.


Second trip:
Catalyst The Protector OR

Now you'll have to make a choice:

Are you losing your lane? Does it look there won't be much fighting going on?
Get Catalyst. It'll tank you up a bit and give you amazing lane sustainability from its passive.

Are you even or winning your lane? Is this a fast paced game and small team fights are already happening?
Get Sheen. Orianna can make great use of Sheen procs in lane as she has very low cooldowns. Her auto attack range isn't the best (550), but if your opponent tries to retaliate, you can almost always hit them with the returning E and shield some of their damage.

If you have the gold left, upgrade your Boots into Ionian Boots of Lucidity, if not, upgrade it your next trip back.


Third trip:
Catalyst The Protector
OR
Buy whatever you didn't buy the second trip back.
Also, start building either Banshee's Veil or Rabadon's depending on how the game is turning out. If you're ahead, get Rabadon's to greatly enhance your damage. If you're dying, or they have lots of stuns, Banshee's Veil will be a great asset to you in team fights. You're already quite safe with your range, Banshee's will keep you from being focused should a stray stun land on you.


Note:
Anytime you're losing your lane, buying some:
AND
Will help you hold your lane. Don't be stubborn and stick to the build, it's not worth it if you're being zoned and not farming.


By now, the laning phase should be over.
Go back to buy items when things are slow, DO NOT blue pill if there's any action at Dragon, Baron, or in a lane. And for chrissake, DO NOT ever show your enemies that you're blue pilling. "Oh look, Orianna blue pilled, let's Dragon!"
Sight Ward
And wards are always important, don't forget it.


At this point in the game, your opponents should have some kind of MR. If so, get:

To keep your damage output high.


If there's still minimal MR (Merc Treads, and a Veil on their tank), get more AP.

Zhonya's Hourglass is interesting on Orianna, if you ever get caught out of position and flash can't save you, you're probably dead with out without Zhonya's active unless your team is close enough to come to your rescue. Nonetheless, it gives great AP and Armor, and you never know when you might need the active (It's like a giant middle finger to Karthus).

Rod of Ages is a good choice if you didn't build a Veil, even if you did, RoA is still a good item to get. HP to tank up a bit, and a good amount of AP for damage. Mana incase you need more, though I never seem to need it.

Rylai's isn't too great on Orianna. None of her offensive skills are single target, and despite her low cooldowns, a constant 15% slow on a few enemies doesn't justify the cost. Your W provides you with all the slow you should need, but just know that Rylai's is an option if you find yourself in a game where slightly slowing most of the enemy team would help.


As for your Philosopher's Stone, you can sell it for other items, or upgrade it into a:

For addition CDR, and a very useful active.
If you get Shurelya's Battlesong, you'll want to sell Ionian Boots of Lucidity should you have it, as you already reached the CDR cap. -Thanks to LiesBelowMe and Temzilla
Other boot choices include Sorcerer's Shoes for more damage, or Mercury's Treads for survivability.


Finally:

Is a strong item on Orianna. Her low cooldowns allows her to make good use of Lich Bane's procs, and the item itself gives AP, move speed and MR, all very good stats. However, remember Orianna's 550 range. In order to use this item fully, you need the skill to be able to jump in and out of fight without getting focused. Proper usage will greatly increase your damage output, but improper usage will get you killed. Use it wisely.


Why I don't get:

These items require you to be pretty close to your enemy constantly in order to deal damage, and although it's true that Orianna's passive improves your auto-attack damage by a decent amount, it is extremely dangerous to stay close to the team fight auto attacking. The longer you stay near the teamfight, the greater then chance of you being focused. Lich Bane is the only exception since as I said before, it doesn't require you to stay in the fight, it lets you weave in and out of the fight, something you'll have to do eventually to make the most of your skills.

EDIT: After watching some other Oriannas and a few tests, I find AS on Orianna to be somewhat viable depending on the enemy team. If they do not have any strong distance closers/minimal stuns, than "battle Orianna" can be used for more DPS than "support caster Orianna". However, if your opponents have very little distance closers or stuns, I wouldn't imagine them being very hard to beat anyways. AS is also extremely strong in lane, but by the time you buy one of these items, laning should be nearing completion.


Testing:

Orianna's spammy skills are perfect for charging an Archangel's, but I have personally never needed the mana Archangel's provides. It's a very heavy investment, even more so when you don't use too much mana. It might however, give a better AP to gold ratio then some of my other choices. I'll test this out ingame.


I absolutely despise getting stacking items when I'm playing seriously. It makes you scared to take risks that could benefit your team, and makes you much less willing to commit to anything to "protect my stacks". However, if the enemy team does not have some kind of distance closer, long ranged stun, etc, and you're confident in your kiting abilities, Soulstealer might be viable. I still don't recommend it, but if you want it, make sure to sell Philosopher's Stone to tank up a bit. Force of Nature if you're dying to magic damage, Randuin's Omen if Xin Zhao, Master Yi, etc is on your ***. If there's a champion like Kassadin, LeBlanc, Olaf, on their team. Don't even think about getting stacks. Even if they have to die, they will go Sparta on your ***.


PS:
sight ward
Get. Wards.
They're. Good.

I take a point in Command: Attack at level one because it offers the most damage and utility should there be a level 1 teamfight. Command: Protect is too weak at level 1 and requires a teammate to be in the enemy team for it to do damage. Command: Dissonance is just bad at level 1 because it actives on Orianna herself, as you'll lack your other skills to move The Ball around.

After that, I prioritize Command: Dissonance as it does the most damage and the slow/haste is extremely useful. Take a point in Command: Protect at level 4 to maximize your ability to move The Ball. Remember that using Command: Protect sticks The Ball onto an ally, allowing you to cast Command: Dissonance to haste them instantly.

Take a point in Command: Shockwave whenever possible, then upgrade Command: Dissonance, Command: Attack, Command: Protect in that order.


Note:
If your team lacks a support, you might wish to prioritize Command: Protect over Command: Attack to enhance your shield's power, but I haven't done this much, so I'm not sure exactly if it'll be worth it.

Orianna's laning phase is pretty strong, but don't get arrogant, you're still very killable.

Tip: The Ball itself has vision. You can use it to check brush. The Ball can also be sent into impassable terrain. This can be utilized to attack the enemy with The Ball from an unexpected angle.

Starting with Sapphire Crystal and two Health Potion allows you to use your skills to harass often. A good and pretty obvious tactic is to move The Ball behind their melee minions, or to the side of the minion wave. This forces your enemy to get close to The Ball if they wish to last hit, making it extremely easy to hit them with a Command: Attack > Command: Dissonance combo.

Tip: Look for when your opponent goes for a last hit, when they stop to attack attack, the chances of them being able to dodge a Command: Attack > Command: Dissonance is very low.

You'll probably want to not be too aggressive until level 3 since your damage doesn't get too great until you level up your Command: Dissonance.

Try and keep your enemy between you and The Ball. This way, if they try to harass you, you can negate some of their damage while hurting them too with Command: Protect. If they keep fighting you, it should be easy to land a quick Command: Attack > Command: Dissonance before backing out.

Don't trade auto-attacks with your enemy (Unless a stupid low AD caster wants to). Your passive might seem like it encourages auto-attack, but your AP early game is so pathetic that it'll probably result in only 2 points of extra damage.

Of course, harass with auto-attacks as you see fit. If you land a Command: Attack, chances are, your opponent will try to move out the way to avoid a Command: Dissonance, prefect time to toss an auto-attack in for extra damage. These small hits will add up very quickly. Don't underestimate it. This becomes even more deadly after you get your Sheen.

Hopefully you won't meet an opponent that'll completely crush you in lane, but we all remember the first time we fought Karthus right? Yeah. If that kind of situation happens, grab a Doran's Ring or two and a few Health Potion. Use Command: Attack to last hit if you have to.

Once team fights start happening, you'll want to be in the back of your team.
Orianna's range with The Ball is amazing, and should be used to your advantage.

Send The Ball into the middle of their team, then have Orianna back away while casting Command: Dissonance. After that, you'll want to "yo-yo" in and out of the battle to cast Command: Attack and use your Sheen or Lich Bane proc. Cast Command: Dissonance when you can hit multiple enemies, or slow/haste enemies/allies strategically. If someone is trying to run away with low health, toss The Ball at him and slow him, allies chasing him will be hasted as they run through Command: Dissonance.

This skill of weaving in and out of team fights is something you have to learn with time. You can't get too far away from the fight or your damage/buffs/debuffs won't be used fully, but getting too close is dangerous. Practice and clear thinking is what'll allow you to effectively use Orianna (And most other champions too).


When to use your Ultimate:
Command: Shockwave is not the most amazing ultimate in the game. The AoE range is average, the damage is nothing special, and the knockback/stun is minimal. However, it still serves its purpose as an AoE stun/disruption.

If your team has someone that can get right into the middle of the enemy team, cast Command: Protect on him and use Command: Shockwave coupled with Command: Dissonance after he gets in there.
Examples: Alistar, Xin Zhao, Shen, Akali, Kassadin, Katarina, Nocturne, etc.

Notice that these champions are NOT all tanks or good initiators. However, they ARE a good person to use as the focus point of your ultimate. Just make sure that you stay in range so you don't embarrassingly cast your ultimate on yourself because Katarina's Shunpo just took her out of The Ball's maximum range and teleported back to Orianna.

Make sure you synergize your ultimate with your teammate's skills. If they have a reason to be in the middle of the enemy team, chances are, they have some kind of AoE they want to use. Make sure to not stack your AoE disables.
Examples: Amumu, Alistar, Galio, Malphite, Jarvan IV etc

On the other hand, some ultimates will benefit if you cast your ultimate along with theirs.
Examples: Fiddlesticks, Katarina, Rammus, Swain etc

Note: On the otherhand, don't ult along with Swain's snare. That'll be silly.


Using your Haste/Slow:
Command: Dissonance provides a powerful haste/slow. Think of it as putting down a Shurelya's Battlesong active effect on the ground for your team while also doubling as a Singed Mega Adhesive for your enemies. Although in laning, this skill is used to harass due to its damage, in a team fight it's most important to take advantage of its utility.

If your Amumu or Singed is trying to initiate, drop a Command: Dissonance right in between him and the enemy team, pop Shurelya's Battlesong as well if you have it. Unless they have hard knockback esquired CC, they're not going to stop a 700 speed Singed from flinging their carry.

If a teammate is caught out of position and is trying to run away from a gank, use Command: Protect to attach The Ball to them and shield them, then use Command: Dissonance to haste them while slowing any enemies who would keep chasing them.


Important:
Do not run into the middle of a teamfight.
There is zero reason for Orianna to be in melee range of any enemy, as she can use allies as the focal point of her skills, or simply toss The Ball where she wants with Command: Attack.

Only get close if you're sure you won't get bursted to deal, like if you're chasing a 50 HP support champion. This build will let you take a few hits, but if you get focused, you will still melt away instantly.

Remember Command: Attack damages enemies The Ball passes through, not just where it stops. It's pretty obvious, but many new Oriannas tend to miss it.


Quick Recap:
Stay out of range of enemies, poke with your spell and Sheen/Lich Bane procs.

Orianna has a unique skill set that requires more micromanagement than most other champions. She has a rather steep learning curve if you wish to learn all her tricks, but I find her to be extremely enjoyable to play.

Oh, and I like her lines.

This is my first guide on Mobafire, don't forget to vote, leave a comment if you think something can be done better, and uh...
Please be gentle? I have sharp things.