Best advice I have is to either start paying real $ for credits and get those cards yourself, or do free credit offers (like surveys). I myself have been doing those offers and already have pretty decent cards. If you get lucky enough to nab expensive cards from packs, you'll do much better.
It can get frustrating to face these seemingly godly cards just remember, the cards dont matter (obviously not if your rocking nobrocybix bunny robin ect) if your cards are playable, it may seem that you have the disadvantage but you can still come out win wins. id suggest try out some cheap manipulation clans (attack or power)