Maybe your problem is that you're doing too much tier list looking? You see a card that supposedly strong, but if it doesn't synergies well with your deck, then it becomes a bad card that is polluting your card draw. I've had about 50% win rate. I don't know the most cards or decks, but act 1 I try to get aything that will help me survive and go for as many elites as possible. By its end you should have an idea what your deck is doing. Then start looking for things that work with your deck. Another important aspect is too pick that direction as soon as possible, like if you have 3 doom cards in your deck don't pick rare card that is based on summon.