I don't play galio personally, but you seriously will win teamfights by flashing into the middle of the enemy and ulting.
Brand needs to stay farther away. His skillshot stuns if they are ignited, but is still a skillshot and does bad damage compared to other abilities, so get an early point and max it last. Don't put all points into W or E instantly, as both have their own situational uses for a lot of early game. The one that instantly hits the target is great for poking and setting up other abilities bonuses. You get the most use out of it early, but it doesn't hurt as much as his delayed burst area of effect one. I usually get 2 or 3 points in the targetable, then max the AOE, then finish the targetable.
Use his ult as you see fit. Its cooldown isn't terrible, but it really should be saved for when you know it will be able to bounce.
You need mana. Get something for mana and/or mana regen before too long, or make sure your jungler is giving you blue buff. If you don't build regen, you need it almost as bad as Anivia and Swain. --- The guy who thinks Karma is a viable champion. Hero's aren't made. They're cornered.
Brand, for sure. Spells don't have spam-ably low cooldowns, different combos for different situations, Q can be blocked by minions, somewhat close range and squishy.
Galio isn't that tough. Knowing when to use his ulti is about as taxing as it gets. E to harass or support, W to boost your own damage or protect an ally, Q to blow up enemies / minions. --- LoL: Syndra, Orianna, Rumble, Rengar, Fizz, Janna, Ezreal, Kog'Maw, Vi, Ahri, Twitch, Volibear, Amumu, Irelia, Galio