Lulu Runes explained
There's one set of runes for Lulu on patch 14.12 that is the clear favorite for LoL players and pros alike. The best Lulu rune paths on the position 
Support are 
Sorcery as the primary path and 
Inspiration as the secondary path with a pick rate of 79%. Besides picking runes on Lulu you should learn how to play Lulu and if you are interested in pro matches take a look on how a pro builds Lulu. If you want to discuss 
Lulu then you should visit the champion subreddit.
Lulu runes from primary path
Sorcery empoweres abilities of Lulu and increases the available champion resources. Most of high elo players – and our LoL pros in the the major regions – have agreed that 
Summon Aery is the best keystone rune to run on Lulu. This keystone rune adds more poke damage to your abilities. And additionally grants an extra shield, whenever Lulu empowers or protects an ally with abilities. Other primary runes on Lulu are 
Manaflow Band, 
Transcendence and 
Scorch.
This is usually followed up by taking Manaflow Band for additional mana and mana regenaration. Transcendence for some more Ability Haste. Scorch increases your control in the early game.
Lulu runes from secondary path
When it comes to your secondary path, most Lulu players prefer to go with Inspiration. Inspiration opens creative opportunities on Lulu troughout the match. On the Inspiration path, the best runes for Lulu are 
Biscuit Delivery and 
Cosmic Insight.
Biscuit Delivery is a great rune for laning as it gives additional health and mana, which can help in more aggressive lanes. Cosmic Insight grants summoner spell and item haste.
FAQ for Lulu Runes
Which is the best keystone rune on Lulu?
The best keystone rune on Lulu is Summon Aery. This Lulu runes setup is then referred as Lulu Summon Aery.
What runes does Lulu use?
Runes from the paths Sorcery and Inspiration are the most used runes on Lulu. For the exact pick rates of Lulu runes used, you have to study the rune distribution presented.