Shikamaru is a young man with dark eyes and hair and is dressed casually in a green jacket with a white undershirt and a small scarf around his neck. His jacket also features the distinct spiral of the Uzumaki Clan. He has a pair of brown pants and sandals as well. To really bring out the details of the design, I suggest using shades of green for the jacket, white for the undershirt and scarf, and light brown and beige for the pants and sandals. Using a lighter shade of green can help highlight the Uzumaki spiral in the back, while adding darker tones to the edges of the jacket, scarf and undershirt can help give them definition. For the hair and eyes, you can choose darker shades of brown, or maybe even black. To bring out the details more, you could use shading and highlighting techniques such as cross hatching and stippling.