I have reached level 61 from level 36 just in a week with 1 or 2 hours gameplay everyday.
Focusing on Raw power and make enemy think they are winning. Its like ART OF WAR. HIT YOUR ENEMY WHERE THEY AREN’T. They will think you a noob or stupid. They will get excited and boom you are winning. Always use scarlet witch in round 3 if you dont have a bad location. If you got a bad location in round 2 use it then... And for other cards.. Try to use vision less and spider-woman more to reduce enemy card power where they have 3/4 cards.