I think you should start buying Chaos Legion packs, get familiar with the game, and then develop a deck that best suits your playing style. For example, I prefer Earth and Death decks, but since Djinn Oshanuss I've been playing the Water deck a lot.
!PIZZA
Thanks so much @drunksamurai! How many packs do you suggest I'd need to move up to bronze II?
Try 5 packs for start, and don't forget the potion bottles that increase the chance of gold and legendary cards.
!PIZZA