Sherlock and John

Sherlock Holmes - Height and build. Tall and quite slender, even skinny.
Hair. Dark, curly.
Skin. Pale.
Eyes. There's a nuance here: Cumberbatch himself has a condition called sectoral heterochromia (where a section of the iris is a different color). Because of this and varying lighting on screen, the character's eyes can appear blue, blue, or even have a green tint.
As for the clothes, the image turned out recognizable:

Under a long coat (the Milford model from the British brand Belstaff was used in the series) is a black suit.
Shirt without a tie.
Often a dark blue scarf.
Sometimes appears wearing a deerstalker hat.
The costume designers tried to make the outfit iconic: a laconic yet expressive silhouette emphasized the hero's eccentricity.

John Watson from the BBC series Sherlock is a man of about 30 to 38 years of age, of average height and build. He has blue eyes and ash-colored hair—either naturally or due to stress and military experience. His hair is often unkempt, but in the final season, John began slicking it back.

In the first season, he often wore a shirt and a leather jacket or sweater, but later began to dress more formally.

The role of John Watson was played by British actor Martin Freeman.