specialize
To focus on becoming very good at one specific thing.
To specialize means to focus your time, energy, and practice on becoming really good at one particular thing rather than spreading yourself across many different areas. When a doctor specializes in treating children, she becomes a pediatrician who knows everything about childhood illnesses and development. When a restaurant specializes in pizza, they perfect their dough, sauce, and toppings instead of offering every kind of food imaginable.
Think of it this way: you could practice five different instruments a little bit each week, or you could specialize in the violin and become exceptional at it. A student might specialize in math and science, spending extra time on those subjects because that's where their interests and talents lie. Professional athletes specialize in their sport, dedicating years to mastering specific skills.
When you specialize, you become someone others turn to because of your deep knowledge or skill. A general store sells a bit of everything, but a bookstore specializes in books. A regular lawyer handles various cases, but one who specializes in environmental law becomes the expert people seek out for those specific problems.
When you specialize, you're making a choice about where to direct your focus and energy, betting that going deep in one area will serve you better than staying shallow in many.