This is only for Galio top. Have at least a Mastery 3 of him:
#Build Path
If team mostly consist of AD, go
.
if enemy team has way less CC.
If team mostly consists of AP, go

.
is optional if you need more healing/sustain with your W.
#Skill Order
In most of my games, I max both QW at each level one by one, as in Q-W-Q-W-Q-W. Usually because Galio is easy to burn mana with for starters, and he is a pretty easy guy to get bullied at top lane, so having sufficient mana(still with decent damage anyway) & your W which keeps bitch-ass pokers like Rivens to deal almost to no damage.
You can sustain faster in lane simply by making minions focus you during your W.
Combos
I don't know what a guy like Galio can make such LC$BigPlay$$. But usually, as long as you have good accuracy with Q, then you can typically just spam everything you got on him. The only thing important about Galio's kit is his ult. In most giant teamfights, it's best to either use E to get into the fray or Flash in so that you can land your ult on the most enemy champions available there. Do note that a
or a
pick is essential if you're going up against an enemy comp with tons of CC on them, especially champs like
.
#Favourable Matchups
Her damage typically almost does nothing if you max your W to at least 2 points. Juke out her shield and then land your Q would force Riven to recall early. Try not to ult on her whilst she is in the middle of her 3rd Q cast time.
He's like a tiny lil Shen, due to his E passive(which acts like Shen's Q) that keeps you sustain in lane even more with the steady heals from your W, and the fact that Teemo is squishy enough to get nuked(a little...) from your Q. Also, he's Ap(duh), means you can rush for MR items like

This is kind of a 50-50 matchup. After you see him going to EWQE, rush out your W to be dealt less damage & then try punishing back with your QE. But at most times, try to save your E for escapes since Renekton can simply double E on you for an empowered stun. And most importantly, do not ult when Renekton's W is at the ready.
#Unfavourable matchup
There's really no point in poking him due to his passive & natural high defence stats, since you'll just be wasting mana on him. Kind of a big-ass bully. If he manages to Q you before you can hit W, then you're really going to have a bad time.....
Same concept as Garen. Nasus can simply Q free farm as much as he wants since your pokes hurts as much as a finger flick. Best to call out your jungler more often when laning against him as Galio. Good news is that he does not have any interruption CC. Remember this fact the next time you face him in giant teamfights.
It's a pretty horrific matchup for the Sentinel here. Tahm Kench can be pretty sticky due to his Q and the ability to nuke you down with his W(since most of the time you may be forced to build HP, making Tahm's W do more damage), and your pokes also do nothing against him due to his E heals. Also best to call out your jungler more.