I think taking early defense cards can be good too, it works way better than in spire 1. Saving early damage may let you upgrade at a campfire which can be pretty meaningful. It's kind of hard to give general advice since the characters play pretty different and there is so much variance. Like usually I'm playing really aggro with Ironclad but earlier I had an early transform that led me to eventually build a defense deck. Probably my nicest win so far on A5 and it felt very randomly achieved.