Pros: Great Survivability in lane
Excellent in last hitting due to smooth attack animation and Passive Skill[Clockwork Windup]
Strong champ throughout the whole game
Many Escape Mechanisms( Skill[Command:Dissonance speeds you up while slowing enemies down]
A spellcaster with strong auto attacks o.0
Great in teamfights as long as you remain behind the tank.

Cons: Skillshot orientated hero. Where you aim your Skill[Command: Attack] is key.
Slightly hard champion to play
Will die really fast if focused

Orianna The Lady of Clockwerk it currently the newest champion out in League of Legends, and finally another champ that doesnt cost 6.3k (costs 4.8k IP). Orianna is a good solo laning hero with strong spells and good laning survivability and farming.

Just a screenshot of how lethal she can be:

Flash: flash is always a great spell to have, good for both initiating and fleeing battle along with the 21 masteries in Utility its cooldown is quite decent.

Ignite: Like Malzahar, Brand or Annie, ignite is essential. Not only is ignite a great source of damage but it also lowers magic resist of those who are ignited. All of Orianna's skills are magic, INCLUDING her passive, you work out the rest ;)

Ghost: flash ghost is also a good combo and you can pick ghost if your new to Orianna and not confident in your skills and need that extra survival boost :D

If your planning on using other summoner spells such as Teleport, clarity, exhaust, Clairvoyance, Cleanse, although untested seem fine. Summoner spells not mentioned here are advised to be avoided (unless Ive missed something key).

The item build I outlined was inspired from watching HotshotGG playing this champion and adapted to my liking. Not only did hotshot use it effectively and owned but I too have tried it multiple times with flying colours. It may look strange at first but rest assured its viable.

Reasons behind the items:
Regrowth pendant is an excellent first item as it allows great survivability combined with Skill[ Command: Protect] at level one giving you an additional +10armour and magic resist you can stay in long for a long time. Her passive and attack animation make it easy to last hit
Note: The defensive items are due to Orianna being fairly weak at the start but becoming progressively stronger as the game goes on.

Philosopher stone: Not only does it provide great regen it also give 5 gold/10sec which is great early on for extra income and laning power. Later on you can make it into a item[Elisa's Miracle] for only 400g! which gives 10 more mana regen/5sec AND 25 Tenacity!!!

Rabadon's Deathcap: The most strongest AP item out there +155AP + 30% more AP along with Oriannas great scaling on her skills means this item is a MUST! Although it may not be easy to get so early in the game. Just remember to last hit, I usually take mid lane so theres no on interfering with my last hitting and it becomes a breeze, respond to potential ganks. Observe the map often and check for enemies on low hp or are over extending.

If you plan on selling the Dorans Ring. Morello's Evil Tome, Nashors Tooth, Lichbane, Deathfire's Grasp are all viable last items to pick. It all depends on the situation.
This is only a quick draft, more info on item choice may/will be added later depending on viewer needs.

Skill sequence is pretty average max Skill[Command: Attack] first and then max Command Dissonance while getting Ult whenever possible. The only difference is I get Skill[Command: Protect] first [a good skill even for lvl 1 ganking as it does around 60dmg to enemies it passes and also gives a 90hp shield]. I first saw HotshotGG getting Skill[Command: Protect] at level one and thought to myself, what a stupid first skill! BUT I was wrong (obviously) because firstly, Skill[Command: Attack] only does 60 dmg lvl 1 :( and secondly Orianna at level one has 11 armour and 30(i think) magic resist. So the +10 armour/Magic resist from Skill[Command: Protect] is great + you can shield yourself for 90hp when you see an attacking incoming.

A Good Combo to use, Q R W E
Hits the with ball, Drags in with ult, aoe slow(Great for teamfights when everyone is bunched up by your ult), ball shields someone and dmgs anything it passes.
Great form of burst, if done correctly along with ignite they should drop from 100% to 0 (excluding tanks ofcourse :P).

Skill[Command: Dissonance] speeds up your allies while slowing enemies, Skill[Command:Attack] moves from point A to point B if not picked up, Skill[Command:Protect] shields the target and transfers the resistance bonuses to them, so you lose it whilst also damaging anything in its path. All these unique skills make up so many combination of techniques and strategies.

Tip: Use W to get to places faster :D

Positioning in team fights is key, you must always try to predict the enemies next movement, ulting the max amount of enemies possible and shielding important team members. Maximising the output of your hero can come in the form of shielding your ally whilst trying to hit as many enemies the ball passes, team coordination on who to focus and positioning, rotating who buys wards, or letting the support buy them.

Overall Orianna I a very interesting hero with many unique skills making her very enjoyable to play. Skill[Command: Attack] will take some getting used to and also figuring out all the combos you can do.

This is my first post, I dont know how to get all those pictures for each section but I hope you enjoyed this guide. Also please post your thoughts about my guide and possible improvements.
Remember, Practice makes Perfect! :D