Welcome to my first guide, starring Orianna. Any feedback is appreciated. I've had success with this build, but I'm not a pro by any means.

Season 3 Build

Purpose of this build: Support. Not mid, though if you are by yourself in lane that's good for gold, but you'll need lots of ganks. As support, you should still be able to get kills (not kill-steals!) and hold your own against aggressors, but for the most part you want to support your AC (etc).

Orianna is very squishy and relies on mana, so you want regen items and mana items. Also, like many support, she needs a gold over time item to afford everything; it's the first thing I buy. With my build, the priorities are AP, mana, armor, and magic resistance. The item order of this build is what I would suggest, but you may want to buy them in different times according to how you play. (If you go mid, you could skip Philosopher's Stone, by the way.) It's very likely that you won't afford all these items, but in long games you might need the extra edge these items give.

Sell Philosopher's Stone later, when you need to buy Lich Bane or perhaps Athene's Holy Grail (if you have potions/wards taking up space). You'll also want to buy health potions near the beginning of the game so you can stay in lane. Few to no mana potions are needed if you pick Clarity.

Mejai's Soulstealer is the best AP item for Orianna because, as a support, you'll get lots of assisted kills, and that will give you an AP boost for very little gold. Just try not to die! (Alacrity will help to get away.)

You may also want to think about getting a Sightstone if you are playing a meta game and need to put up wards.

Like other guides say (or at least the ones I looked at when starting Orianna), Attack is priority, then Dissonance, then Protect. Always level your ult whenever you get the chance.

These may not be the best, but I prioritized those I thought would be useful for Orianna. Comments welcome!