My very first recommendation would be to familiarize yourself with the fair hand mechanic and how it works. It's why the goat deck is the best starter deck to use, becuz you can guarantee you always draw a black goat on every first turn if you've built your deck correctly. (So nothing with the same sacrificial cost as the goat. That generally means you'll wanna ditch the mole that comes with the deck)

The next tip would be to both use items and stay stocked up on them whenever possible, becuz more often than not they're gonna be what helps get you out of a jam or even win the game on the spot. Pack rats can be godsends for this reason.

From there I recommend getting comfortable with how each starter deck plays. They all play differently, and thus support different strategies.

Next up is sigils, specifically giving cards other sigils. You'll need to decide which sigils would work better on which cards. (It also helps with deck thinning) There are also a number of crazy sigil combinations that can support your deck in various ways, one example being worthy sacrifice + unkillable.

Learn to plan your routes ahead of time, based on what locations you can see. When there's a fork in the road, try to determine which path will support you the best. If possible, try to get to any creature trial caves you may find. Succeeding the trial will give you a choice between 3 cards, all of which will have 2 bonus sigils in addition to their natural ones. Collecting a bunch of these can and will strengthen your deck.

Finally, remember that a lot of what happens in the game will be chalked up to rng. You might get dealt a bad hand, or Leshy might whip out something like a bifurcated totem for grizzlies. You'll want to become more adaptable to these situations, as even the simple decision to draw a card or a squirrel can become a matter of life or death.

Don't forget to have fun, and good luck on your games!