Early game: Get a joker that gives you a big mult (e.g., Half Joker w/ +20 Mult for small hands). This will allow you to survive while you build out your points engine. (You can survive with flushes in the early game, but it can get harder to win with flush later, due to Bosses, unless you have flush friendly Jokers and a large hand size.)
Mid game: Generate $$$ so you can buy planets and tarot cards. Once you're happy with your jokers, you want to level up the hands that work well with those Jokers. Try easier hands like Two Pair or Pair or High Card. (Assuming you can generate enough cash to level up those hands.)
Tip: Blue Seals are helpful!
To Win: Look for jokers that get you increasingly higher +mult or xmult for things you'll do anyways. There are jokers that increase mult for using tarot cards, or jokers that increase xmult for adding new cards to your deck.
Tip: Steel cards are also awesome.
Tip: If you have an xmult joker, move it to the right side, as jokers trigger from left to right. You want to multiply after you add!
Disclaimer: I have not beaten ante 11 yet. I can get a couple million points with my strategy, but 7+ million is too difficult. I don't see an easy path to naneinf (not a typo). I guess I'll need to give up and watch some YouTube guides as some point.
I feel like I win about 50% or more of my games on regular white stake difficulty. I've won some red stakes, but I don't really feel a need to make the game much harder. I think if I played it safe I could win 75% or more of my games on white stake. The reason my win rate on base difficulty is lower is because I like to try weird strategies with different jokers.
The amazing thing about Balatro is.... there are many many different paths to a victory. Everyone has their own favorite joker, and it might all be different.
For a long time, I liked two pair hands the most. Now most of my games use pair or high card. I find it too difficult to get to ante 9+ with a 5-card strategy. (4-card flushes are OK.)