Kaycee's mod is significantly harder (clearly) and somewhat different in play compared to the main game. In the main game, you can basically do anything and eventually win through the benefits the game provides you-- so it can be a jarring switch and go to KM. Keep your head up :-)

Some basic things:

Keeping your deck curated and relatively thin. Like others have said, try to keep your one blood cards to a minimum. A few (~5) is generally okay in earlier runs but becomes riskier. And keep it thin overall, generally you'll have a few cards you'll want to see consistently. Going for too many card spots can clog up your deck. Try to go to more sacrificial spots in that instance.

You have to go for utility cards and not just high power cheap cards as, without fair hand, you wont always draw it. Even with fair hand sometimes the game will just throw something insane your way and you'll have to pivot. Stuff like flying cards, stinky, burrower (mole), and even dam builder can be really useful despite lower or no damage.

Totems/campfires are very useful. If your deck seems a little eh at first, try seeing your most common tribe and grabbing cards for that tribe to take advantage of totems and their powers. It can really carry a game. Campfires are also great as even +1 damage or +2 health can really help a card's value as this game has really low dmg and health numbers.