The whole point about these kind of games is about iteration and learning from them. Many people just play very fast and without any reflection, on what actually went wrong. Never forget that all of these games want you to win. Deck building isn't a magical skill, it is just familiarity with the game and it's mechanics. The balance between "do I have enough cards that do something" and "do I have enough resources/time/mana to play my cards that do something" just comes through experience. And if you don't enjoy the experience, it's fine to find something else.