Hello to everyone who is intersted playing Galio.

Galio is one hell of champion. He can be great game changer, if played right and annoyance to enemy team mid champion because of his superb passive.

!!! This will be super "into-the-content" guide, so there will be no flashy pictures or quotes here, just pure information to help you get better !!!

Pros
Good farmer
Fun to play
Nice harass
Good ultimate
Insane shield

Cons
Weak early game
Mana hungry early game

I don't really care what masteries do people apply, but don't be stupid.
You can go with tank masteries with Galio, or Ability Power (AP) masteries. I preffer AP masteries.
My masteries 20-0-10

I don't really care either of the runes, but getting some AP and Magic Resist runes will do well.

Ability Power glyphs Greater Glyph of Ability Power x9
Ability Power Quintessence Greater Quintessence of Ability Power x3
Magic Pen. marks Greater Mark of Magic Penetration x9
Magic Resist seals Greater Seal of Magic Resist x9

You star off with Null-Magic Mantle and one Health Potion and one Mana potion.
Null-Magic Mantle because you get resist to enemies mid champ, and you get some AP od your own (Galios passive Runic Skin )

Then you go on to Chalice of Harmony for more mana regen, magic resist and AP (Again Galios passive plays great role)

BOOTS HERE

FINISH BOOTS HERE

Then you go for Abyssal Mask for more AP, MR and more AP :)
(You cun buy Negatron Cloak if you dont have enough money)

OR HERE

Then you go for Rod of Ages for more health, ability power and mana

Then for Banshee's Veil. It will serve you well when you ult, and you block the first stun, silence or anything that will try to interup your ultimate.

Finish Chalice of Harmony to Athene's unhoyl grail for more mana, AP and MR.

And ya all know the usage of Rabadons Deathcap

Your role in teamfights is to do "tons of damage" Stay behind of your initiator and spam your Q, W and E. When the teamfight erupts, wait for everyone to use their abilities and go in the fights and ult. If you are out of position use your flash to flash into the storm. After the ultimate, keep spamming your spells.

If you are running from or chasing enemies use your Q to slow them and E to get speed boost.

Early game try not to waste mana, unless you are sure that you will get multiple minions with Q Resolute Smite or E Righteous Gust and you will hit enemy champ, because Q takes a lot of mana, and it isn't nice when you are out of mana.

But when your jungler gives you the blue buff. Be free to spam the hell out of your keyboard.

Mid and Late game
Let the spell spam begin.
With the Athene's unholy grail and Rod Of Ages your mana will be over 50% at most of the time even if you spam. But if you only "last hit" with Q and E it will be over 80%.