My strategy, kind fail-proof.
Get frost vs monster decks (counter-melee)
Get fog vs scoia-tel (counter-range)
Get rain vs northern (counter-artillery)
Having a spare frost is always beneficial.
Redraw weather cards not to your benefit vs said enemy.
Redraw "grunt/basic" units for medics, special cards, horn, decoy.
Get as many draw cards and decoy cards that you can get in your hand.
Play all draw cards first round to increase your deck.
If they play draw cards - decoy them and use them to draw even more.
First round - don't commit too many units. Let them waste cards. Good combo is to freeze your own draw cards given to opponent.
Medic is a fantastic choice for decoy - use medic the 2nd round to redraw a previous unit, then decoy your medic and get another one out!
Also - keep your deck size to the minimum available, you dont want to draw peasants and crap.
IMO for leader - siege master foltest is supreme.
I often get 14+ cards on my 2nd round using this tactic. By decoying your enemy's draw cards placed on your border.
BEST CARDS:
Decoy
Draw cards
Medic