Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Congratulations! If you're here (and you're reading this) it means you've taken the first steps into Orianna. Which might also be called taking the first steps into greatness. Or insanity. Orianna is unlike any character that I've seen and yet, so similar to a number of champions. Without further ado, let us begin.
Actually, before we get any further, I absolutely HATE the "multi-chapter" format... I'm keeping this in one, nice, solid block. Sorry for any inconvenience this may bring about. Also, this build is not meant for holding down a lane (though it's perfectly capable of doing so.) It's more of a harass build, where you're meant to be all over the map, gunning for Champions.
Orianna is a character that feeds off mana. I can not stress that enough. Also, on the same note, her abilities are easily her strong point. While that can be said about any character, keep in mind that some characters hit like trucks. While I'm sure you can build her that way she is not a heavy-hitting auto-attacker. She's got a solid attack, but her primary damage is going to come from the Ball. So, since we're building her for abilities, the bonus attack speed for the auto-attack is a nice addition. But the mp5, the ability damage, and the cooldown reductions are absolute MUSTS. You'll hit harder and faster with less downtime.
For this build, Orianna makes a 15/0/15 hybrid look good. I can't really justify this with words, but the spec should speak for itself. Buffing ability power and decreasing cooldowns and buffing mana in general (regen and base) is always a good thing.
Clarity and Teleport. My favorite combo for Orianna. Running low on any character for mana is always a bad sign. Pop Clarity and keep going. It's definitely changed battle outcomes when enemies rush in thinking I'm now defenseless. Teleport; Need to go back to heal, buy something, or you died? No problem. Quickly get back on the front lines!
Skill Sequence! Getting that little ball flying around is your number one priority. Command Attack is the staple of Orianna's offensive capabilities. Dissonance is a wonderful aoe that in time, makes for a great get-a-way, minion thinner, and a killer technique. These two skills should be your primary focus. Shockwave is a fun spell, that can be used as a finisher or a stun. Protect will sometimes save your life, but it's basically the reverse of "Attack" since it brings it back to you and gives you some armor buffs. It's nice, but since attack doesn't require it to launch from you, it can be cast again and again. The Ball takes some getting used to, but you can set up some nasty stuff with it. Launch it a little further than you should so when enemies run, they run into it, and pop Dissonance, followed by another Command Attack and auto-attacks. Shockwave (if you'd like, or need to) and keep going.
Explaining the item choice... I like this part. For Orianna, I absolutely do not like any of the "recommended" items. Again, you'll be looking for things that buff mana regen and life regen, to keep you in the fights and not in your base. The only deviation I could see would be if you went Mobility instead of Swiftness (since you should be all over the map.) The rest of those weapons will give you mana, regen, and better cooldowns in ways that will be sure to bring smiles to you and your team and tears of sorrow to the enemy.
She's a good sniper character that can hold a lane. She's fun to play once you get her style and the way the Ball works to add a variable to battles. However, she is a wee bit squishy and a little difficult to master. But she is a good character.
In summary, this guide will not make you the ultimate God of the battlefield. It will not ensure victories 10 times out of 10. What it will do is give you an insight on how Orianna can be played as a harassing character. How you can spill some rivers of blood and laugh about it. If you'd like to play her holding or pushing a lane, that is perfectly acceptable within this build as well. Go swiftness boots and you can still snipe off those low hp champs. But overall, have fun with this new character. The ball adds a new style that can, at times, get aggravating. But when it pays off, it's well worth it.
Comments and criticisms are always welcome.