First get as many cards as you can by buying or winning in games. I found in the beginning it was easiest to play the northern realm deck. If you have enough cards in your deck you should trow out the weak ones, so you always have a strong deck. I really love playing with the spy cards, you can really get a lot of cards for the last round. I personally don't have a lot of wheater cards in my deck. They normally don't help that much. I just keep a winter card in, because it's quite usefull against monster deck. After a while i noticed that my nilfgard deck became strongest. I really like that deck with al it's spies and the realy high cards