I have no idea either! I'm a level 41 storm wizard and every time I go in ranked pvp, the same things always happen.
My opponet places 1 or 2 storm shields on the first few turns, and without any DoT spells it takes a while for me to destroy them. By the time I do, they usualy just use some treasure card or high pip card and they kill me in 1 or 2 hits, as I only have 1500 health.
Another problem I recently face is people who get criticals every single turn, some of them arn't even that much higher level than me. When a 0 pip spell does 300 damage, it gets annoying.