Question

which pencil(s) should I used for darker hair ..for getting smooth and realistic look​

Answer 1

Answer:

you should use a 2B pencil to sketch i recommend using darker shades for outlining im sorry i dont know much about art :3

Explanation: using dark pencil to outline can make better effects.

Answer 2

Use darker shades of drawing pencils. If it's for hair i'd recommend Shades 7B - 9B of Fiber Castell drawing pencils.