Questions about the gameplay of Heroes 6.

Well, is there a way to speed this up? Otherwise, the enemies manage to defend with 3 stacks in 3 turns, and I just stand there like an idiot, hitting them hard with a club, but I don't have enough magic...

Pay closer attention to what fills the scale. First, it's filled by leadership, so you need to level up the "Fiery Determination" skill. You can also level up "Heroism," and on level 1, you need to hit enemy creatures. From levels 2 to 4, you need to be hit more often.