As a mentor I have watched dozens of junior developers grow. The fastest ones share common traits.
First: they care about the quality of what they ship — they treat code review as a gift, not an attack. Second: they ask "why" — they understand not just that the code works, but why. Third: they build small, real projects.
In the AI era this matters even more: AI can write code for you, but it cannot think for you. Develop your engineering judgement — tools change, principles stay.