Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Let it begin.
Items and Abilities:
Buy your Ruby Crystal as first item and don't look for other items cause you spent all your money for it. Choose a lane and remember you can mid too cause you got 2 ranged and really boring for your enemies abilities: RESOLUTE SMITE and RIGHTEOUS GUST (Q and E).
Choose Q as first skill for 2 reasons: it's ranged and slow enemies so it can be useful for the first blood you are going to try. RIGHTEOUS GUST (E) as second skill to hit your enemies with 2 attacks even if they are turret huggers, you can use it to run away from them if you need to escape, RIGHTEOUS GUST's wind in fact increases your movement speed (for your allies too). When you reach level 3 get your BULWARK (W), you can use it on yourself or on an ally. It will reduce damage taken and will heal you, so if you are low health just put it on your ally when he's going to inc the enemies and you will be healed.
How to use IDOL OF DURAND (R) (it's awesome), 2 ways:
1- In the early game you can use it under your turret and taunt all the enemies who are killing you or who are destroying your turret, this will bring them to half life and will make your turret attack them.
2- In the late game go between your enemies and use it, this will done a lot of damage so you can get some kills and your allies will kill the rest.
Let's go back to our lane.
After you got your Ruby Crystal wait till you have 2k golds and recall, now you can finish the SPIRITS VISAGE and you can get MERCURY'S TREADS. From now your items sequence will depend on the kind of your enemies. Melee enemies? get AEGIS OF LEGION and GUARDIAN ANGEL first cause they will give some hp and armor. Magic enemies? so buy BANSHEE'S VEIL and GUARDIAN ANGEL first cause of their magic resist.
Always remember your passive 50% magic resistance will be tramuted in Ability Power which increases your abilities damage and healing.
When you will have SPIRIT VISAGE, MERCURY'S TREADS, GUARDIAN ANGEL, AEGIS OF LEGION and BANSHEE'S VEIL the game will be next to its end, if not you can get an other item. My suggestion's are: WARMOGS'S ARMOR (for HP), FORCE OF NATURE (if there are a lot of casters), THORNMAIL (if there are a lot of melee).
Why Spirit Visage first item? it gives you all you need: hp, magic res., cd reduction and really low cost.
Why Mercury Treads as boots? Cause you will tank and you will be probably afflicted by stuns and slows, Mercury's help a lot and give you magic res. (and AP due to your passive).
Marks: all Magic Pen. to improve your abilities effects.
Seals: all Dodge, best tank runes.
Glyphs: all Magic Resist. cause it will help you getting less damage and cause they will give you AP(due to your passive).
Quintessences: +32hp, Galio is kinda squishy at start and these will help you to survive longer and to not die ofc.
Masteries: 9/0/21 for 2 reasons: Magic Pen. improved and CDR + HP5 and MP5. You can go 9/21/0 if you prefer.
Summoner's Abilities: Heal and Clarity. Clarity is really good cause Galio's abilities waste a lot of mana. If you don't like Heal you can use Teleport or Ghost, they are good too.
Defending your turret from a mass inc: Spam your rangeds abilities on enemies making them low life and holding the turret while your allies are coming, when they will be there go between enemies and use IDOL OF DURAND.
Low Health but with an ally: Use your BULWARK on your ally when he's going to attack so you can easily get healed and you can help your ally.
When use Heal in Team Fight: 1- when you need few secs till your ulti ready HEAL will help your allies to survive and holding the fight till it will be ready. 2- After your ulti if enemies who survived are still focussing you.
Pushing / Backdooring: Use RIGHTEOUS GUST and RESOLUTE SMITH to fast aoe kill minions, now use RIGHTEOUS GUST to let your allies and minions move faster.
ESCAPING: use BULWARK on you or on an ally to protect him and be sure to use RIGHTEOUS GUST to escape running in his wind and saying to your allies to do the same for a faster run. You can also you RESOLUTE SMITE to slow your enemies.
That's all. Have fun and don't care if you get a lot of assist=)