When you're playing a match card yourself, use it to get rid of something powerful otherwise you're wasting an opportunity. When you're attacking one, use the lowest card you can so that you're not losing anything that could be handy later on. Knowing which cards to match, and when, is the key to success here. The basic mantra to remember is attack high and defend as low as you can without losing a card. Sometimes that's not possible, but try and ensure anything you do lose is doing as much damage as it can before it goes.
Random
It's best to use your random cards as defensive measures. You don't know what the numbers are going to spew out when you play them, so let your opponent take the risks instead by attacking. If you survive you've got a sleeping card that you probably weren't going to use anyway, and it'll slip nicely back into your deck if it lasts the next turn, ready to be used to give your opponent a difficult choice later in the game.
Sacrifice
Sacrificing lower numbered cards in order to send more powerful cards to sleep is a tactic that's going to see you through some tough battles. It means your opponent's best cards are taken out of the game, letting you protect your own. It's also an offensive move, because it means your own powerful cards are free to concentrate on taking out minions that aren't going to do them any damage.
Stay wet
Use your boost cards wisely and you're far more likely to succeed. Nerfing your opponent with the water gun early on will make them focus on taking out the card, leaving your other units free to attack. Remember though that cards remain changed even after the card has been destroyed. Get a card wet once and it'll stay wet throughout the rest of the game. If there's a water gun in play, get rid of it before throwing your best cards into the mix.
Your first hand
The first three cards you stick into the fray should all be medium strength. That way you're best placed to combat anything that your foe throws at you. Try to lead with something like a 5, 6, 7. Not only does that mean you've got some power on the board without chucking out your 8s and 9s, it also means that if you do take a bad hit in the first couple of rounds, you've not lost anything that could change the game later on.
