Turn 1. Do nothing. Turn 2. Use your hero power. Turn 3. Use your hero power. Turn 4. Drop Giant, win gaem.
In actuality, it’s a bit tougher than that, especially as you get into the higher ranks, but the essence is very much the same. You’ll want to mulligan for either a Twilight Drake or Mountain Giant against pretty much everyone (unless you think it’s a rush deck, then go for a Hellfire), and then get them out as soon as possible. After that, just keep things taunted up and try to stay alive until late game – you’ll probably be anywhere from 15-19 hit points depending on who you’re facing. If you get to 10 life, you can drop Molten Giants for free, which makes for some pretty entertaining blocking when you put down a Defender of Argus with them.