So... Orianna. Yeah this is my first guide ever. So why did I make one about Orianna? Simply because she is the most powerful and fun champion I've played so far.

I'll be covering the most aspects that sorrounds Orianna. Keep in mind that this guide is always under construction, so if there is missing something, that's why.

Also I'm not a native english speaker, thus my english might not meet your standards.

Pros

High burst.
Great survivability due to her long range and the spell.
Very annoying laner.
Great CC from her and .
Lots of fun.
A decent support champion too.

Cons

Squishy.
Takes a bit of practice to get used to, however not as much as Riot makes it up to be (and other players.
Her first few levels can feel pretty weak due to the high mana cost and low damage.

I believe the runes are pretty straight forward. Honestly, I've never felt that runes did anything major in the game, thus you can go for whatever runes you feel like. However, I do believe you should go for these runes for maximum bang for the buck:

Marks

These will help you out dealing the most damage you could want from marks. There aren't really any marks that come near these.

Seals

Orianna have a few mana problems, at least early to mid game. These seals helps a lot out. You could go for flat mp/5 instead of per level, but I simply feel that Orianna has a bit of mana problems late game too, so you might as well go for these ones.

Glyphs

Since Orianna's spells are already on a pretty low cooldown, you might wonder why you should get these. Her ultimate has a pretty long cooldown, and that is what really kills her. It's the most fun, annoying, disruptive etc. skill she has, so you want this to be off cooldown as often as possible.

Quintessence

Omnomnom more Magic Pen. Magic pen is basically the best stat you can get from runes for her, so this is pretty much an obvious choice.