The haircut that looks good on someone else is a starting point, not a plan. Four things decide what will work on you.
Head and face shape
Height on top lengthens a rounder face. Keeping the sides tighter narrows a wider one. If your face is already long, avoid stacking too much height on top and let the sides carry a bit more weight.
Hair texture
Straight fine hair holds a clean, defined shape but shows every line, so precision matters. Thick or wavy hair carries length well and hides grow-out, but needs weight removed to sit down. Curly hair needs shape cut into it rather than length taken off evenly.
Your hairline
A receding or high hairline usually looks better with texture pulled forward and a softer front line, rather than slicked straight back. Your barber will tell you honestly what your hairline supports.
Your mornings
Be honest about how much time you will spend. A cut that needs a blow dryer and two products will look worse than a simpler cut you can actually maintain.