Valkyrie is extremely OP since the last balance changes. She is a great counter to bait decks and pretty much any graveyard deck in the game. This deck is pretty good on defence because it has the Valkyrie and the Tesla which are a great combo. Some of the tips that Jigsawqt says are here: if the opponent doesn’t have a log or another hard counter to your barrel then play well on defence and get chip damage throughout the game. You don’t need to rocket cycle in this case because you’re more likely to get chip damage. You need to be carful how aggressive you play with this deck playing Valkyrie and goblin gang at the bridge followed by a goblin barrel can either win or lose you the game. You need to know what your opponent is running and what their cycle is. If you’re against three musketeers and they split them play the Valkyrie into the lane with one musketeer and then princess in the other lane and use log or goblin gang where required.
Princess is a pretty important card and as with most bait decks you want to maximise to value you get from her by defending her however be carful not to over commit on the defence of the princess especially if she’s at the bridge because it can leave you low on elixir.
If your opponent doesn’t have a log or hard counter to this then make sure you use this card to get tower damage throughout the game. If they do have a hard counter then you might be forced to rocket cycle and use princess for chip damage if you can’t out cycle your opponent.
Against three musketeers you should always rocket their pump unless he pumps up late in the game where you could go aggressive at the bridge and potentially do a lot of damage.
Tesla is a great defensive building remeber when it isn’t attacking it is ‘hidden’ so you need to play it slightly closer to your tower in the lane your defending than you would perhaps a cannon or tombstone. It can’t also one shot minions and goblins making it great against the common three musketeer deck or bait.
Valkyrie is a mini tank with splash damage, so she always needs to be played in front of cards to help protect them. She can also be used to tank for your goblin barrel.
Early game you can start out with a goblin barrel to try and catch your opponent with their counter out of hand. If their counter is in hand then at least you know how they will defend the goblin barrel. You should try and figure out what deck your opponent is playing while playing smart of defence and making positive elixir trades. If you know you can out cycle your opponents counters then defend well then cycle as quick as you can to get back to the barrel. You should try and acquire chip damage through the first two minuets of the game, remember to try and always get chip damage with your log.
Later game is their tower is around 1000HP or under then you can often just cycle rockets to win the game while playing extremely well on defence. If they play a heavy tank in one lane then you can go aggressive in the opposite lane with your Valkyrie followed by goblin gang and the barrel on their tower. You can play trick barrels if you think you opponent will fall for it too.