I don't really understand the strategy, but must it be so difficult to win even a single round?
In early rounds, try to buy the best card with every 3 gold you have, and avoid refreshing if you have 3 gold or more.
Try to upgrade the shop early, but not too early (you'll get a feel for it the more you play ^^).
After a few rounds, try to focus on a single tribe and its synergies.
I figured it out. I was missing the part where you drag stuff into play. I thought that since it was an auto-battler, it would do that on its own. Maybe have it tell you if you try to play without any cards?
I did the same thing! Glad it's not just me.