This is my first guide. I wrote it because I see everyday a lot of people, who dont know what to do with "semi-support". Even if they tell me they do know it ;).

However in this guide I will show you my prefered Orianna build and some general informations about how to play support seriosly. My build/s are very flexible and the way of playing depends a lot of your team and your opponents.

What Runes I have to choose?

I answer this question with: It depens on your team, your opponents and your style of playing.

My major Runes for Orianna are magic damage improving Runes. The reason why I use them is, because I think Orianna is not an usual support champ, she is "semi-support" and has, in this case, to deal huge damage in lategame.
Alternatively you can use mana regeneration or "early-game" Runes, dependent on you and your team/opponents.

As told in chapter Runes Orianna is semi-support, so what you should take are masteries, which improve your ability power, but dont take skills like Ignite or Exhaust, because you will have enough other champions in your team who should have them. For supporting we use Flash & Promote.

Some of you may think Promote is stupid, but it isn't. Promote will help you to farm, if you are playing against harrasing opponents, you can push more easily and the promoted creap will tank the tower, thats a huge advantage.

Alternatively you can use spells like Clairvoyance, but it becomes not that nesseccary if you are playing Orianna well.
Flash is usefull because as a supportive champion you have to aid your allies, even if you could die. To prevent dieing too often use Flash to escape, use your map awareness!

The items, everyone does know the best item-build, aren't they?

Items you chose should match your style of playing and the conditions of the game. If you're playing solo mid, most of your opponents will fear your ball, so a simple placement of your ball between him and the creaps will be a great defence, so you dont need a lot of mana in early game.
If you are playing with a mate, then you usually do need more mana then solo mid against an opponents, who is feared of your ball. Take mana regenerating items if your tear of the goddes isn't enough, do the same, if you have mana problems in generall with Orianna.

I usually don't say that you have to do something, but if you're playing Orianna supportive, buy wards! You have to have always enough wards to ward the area around your team, if there is a chance to be attacked by enemies.

The first items you should focus on (after boots) are tear of the goddes and Rod of Ages. What kind of boots you should buy depends on the "potential speed of a teamfight", that means how fast the area the teams are fighting in is changing. Buy Sorcerer's Shoes for a slower potential and Ionian Boots of Lucidit for a faster potential.

At the beginning of the game a Doran's Ring is a good idea. (The ability power at the top is wrong, you will have around 750 ap)

What do I have to skill when?

As always the order depends on you, your team and your opponents.
At first Command: Attack is a good idea. This spell provides you the ability of harrasing from afar.
After you chose Command: Protect if you need more survivability or Command: Dissonance if you want to harras or gank much more, but this is also a good choice if you have to run away often. These both skills are your main supportive skill, speed (de)buff and defence. After take what you think is usefull for you and your team, I usually maximize the sjikks as you could see it top. The reason why I maximize Command: Attack at least is because the other skills are much more usefull for the team and they are dealing damage aswell.

You always have to remember, that you are not a full carry. So if you team hasn't got a good supporter, then it's your turn to improve the map awareness of your team with providing wards.

Place your wards around your team, if there is the possibility to be attacked by your enemies. Put a ward in front of the dragon and in lategame put a ward in front of Nashor too. Use your map awareness!
If you can't afford wards in early game, then use Command: Attack to scout bushes.

Additionally:

Something that is really often forgotten use psychology!
- use Clairvoyance to demoralise the enemy jungler
- harras and prevent your enemies from farming/gaining experience

- don't flame your team!
- say gj, wd, and be nice!
- play as a team!

These are only a few examples how you can use psychology to get a good game.

At least I can say that everything depends on several game factors and your skill level.

I hope you enjoyed this Guide. It was my first so please don't flame me ^^

with a friendly graaaaaaaaaaaaaatz,

Myrmod