Instruction, even good instruction, is not enough. You need to practice that skill as much as you can. Four hours a day is not too much, and for some skills, four hours may be the minimum. There are no shortcuts. You must also practice intentionally, by setting a goal for each practice session. You also need to practice those skills in different environments or situations. Finally, you need to challenge yourself in increasingly difficult situations, and not move on to the next difficulty level until you have mastered the prior level.
Say you are learning to cook. Get recommendations to find the best instruction. Don’t be surprised if it costs a lot of money. Good instruction is hard to find and is immensely valuable. Then begin with cooking simple recipes in your own kitchen. Your practice goals might be making the dish in a certain length of time, or using the minimum number of pots, or making it so that a taste-tester rates it 5/5. Then add complexities, perhaps situations like not using prepared ingredients (e.g., not using jarred tomato sauce but making one from scratch), or being able to accurately measure ingredients by eye. Then once you have mastered simple recipes in different situations, try slightly more difficult recipes.
The key is to practice, and practice with intention about what you hope that practice session will accomplish. You need to spend far more hours practicing than you think you need, and always practice with a goal. You may not achieve that goal in today’s practice. That’s why you do it again tomorrow. And tomorrow. And tomorrow, after that (inspired by Macbeth by William Shakespeare 😁).