[Hearthstone] What is your deck building process?

I'm pretty interested in how people are going about building decks for Hearthstone. Mostly just to see what others have come up with but mostly because mine are terrible (so I'm looking for tricks) xD

So do you guys start with a theme, build around it and see if it works? Is it an iterative process (build something you think might be OK and see which cards work and which don't) ? Or do you mimic decks that have bested you in the past?