A tip I would like to add in is test your strategies. If you keep losing, see what's wrong and what cards you should probably add in or take out of your deck. treasure cards are useful in pvp. You can get something like tc towers or tc weaknesses to throw off your opponent or some sacrifice tc's to take off traps like feint, hex, and curse that your opponents cast on you. See what works best for you and if you keep getting victories, continue doing it.
If you see your opponent cast a minion, you better take out that minion. I was in a match earlier where this guy would tower shield a good bit and my mander minion would help me out by attacking those shields and it helped open up for a good opportunity for an attack.
A funny thing I want to mention is that when your opponent starts complaining and crying and calling you a noob whenever you use a shield or debuff or anything to throw him/her off, 9 times out of 10, your strategy is working and your opponent is getting frustrated and angry and doesn't know how to get past your strategy.