well this isnt a usual card game, you fight your own deck n not the rivals in the first place.
so when adding creatures allways think about how to kill them without takin to much dmg.
usualy you atk first so its possible to 1shot creatures without taking dmg at all.

try to stick on 30 cards, u'll never draw the entire deck so minimum decksize allows better draw.

this game is much about grief, removing atk power from rival, destroying his weapon, dealing direct dmg, steal gold, buffing his creatures, ... might always be a thing.
try to play save:
- count on overdmg or alternative ways of killing stuff ( hint: creatures with 0atk die instant )
- dont expect to keep an equiped weapon in the next capter. cards like bar fight, kalphite emissary, ... (weapon destruction) are in every deck.
- always get more gold than your support needs / play the support asap after gold gain / play completly without gold

the current meta is pretty aggro driven, add some/alot health/armour gain or go for direct dmg as well.

in deck construction there are 3 buttons in the upper right corner. the [ i ] shows your decks rewards. so gold, base atk, heal, armour n weapons you get from paying for your supports or killing your creatures ( this list does not contain card text effects, so you might have more heal than shown )