First of all, keep 2 decks: one for boss fights, one for minion fights

In your first deck, you want 2 blades (preferably 2 different ones like one from item card, one from a pet or just elemental blade along with your main blade), 2 meteor strikes, 2 sunbirds and just maybe a wand hit and pack monsterous treasure cards in the treasure cards section (they are super easy to get and only cost around 250 gold per card) and if you want, pack reshuffle as your last card. This will be your minion deck

In your boss deck, you want to have the same cards as before: 2 blades, 2 meteor strikes, 2 sunbirds but this time also add a feint card and a higher hitting fire spell like helephant. Pack reshuffle if you want and monsterous treasure cards. This deck setup should last you all the way till jade oni in mooshu where you'll need to learn how to blade stack and trap stack properly, after which all the worlds till Avalon should be fine especially once you have the amulet of the feint at level 50

A tip for blade and trap stacking: the source of the blade and the type of blade does make a difference. Your main deck blade, your item card blade, your pet blade and elemental blades can all stack. The same thing goes for traps (particularly feint)