the strategy i found was taking some damage at the beginning so i can make powerful vampire cards, and then getting all my health back while smashing ennemies. i tried some rounds with thorns but i'm not a big fan of it.
oh and also, i don't know if it's supposed to do this, but almost all of the times i had to chose between cards (before a new round) i had the choice between 3x the same card so la question elle est vite répondue