Hello :), I quickly read what my colleagues said and as I haven't seen Color Temperature. To achieve some more "life like" paintings you'll have to introduce subtle variations in tones and colors. If you want to be even more realistic you'll have to be accurate, meaning that parts of the body will be warmer/colder than others, because of blood supply or whatever reason. All objects will have some color variations. To help you could maybe imagine in what type of environment this character is, what is the type of light, is there colored stuffs that reflects light around,... ? Getting realistic is adding accurate informations, even if they are simplified. Hope this helps.

Can you draw a realistic face based on a photo? If you can post a work product of that, it'd be helpful. If you haven't, I'd do that first!

Besides the black outlines and that the more reslistic drawing you want to have the more you need to show gradually changing in value instead of black lines. i see a few things in the structure of the face: 1: Nose. The nose you drawn is very straight with the same thickness down and up. A reailistic nose is much thinner between the eyes. Generally a bit thinner than the distance beetween a persons eyebrows. 2: Eyebrows. Besides outline and the lack of texture it looks like they floating in front of the eyes. Depending in what expression you want him to show you either need to make the eyes show it too or move the eyebrows up a bit. 3: Ears . The head and face overall shows that naruto holds the head straight watching forward. But the ears is a bit high up as if he lean the head forward watching down. So what you should do here is also depending what you want him to show. 4: cheekbones. In manga the cheekbones always is very soft and the chin a bit pointy. For more realistic look you can make the cheekbones more distinguished. More like the left side than the right. I Hope this helps 👍🏼

I think that its definitely on the right track! A few thinks of note that might help; Texture: You've started to show texture in the hair and headband but you could continue this into the shirt. Look at reference of these materials and try to figure out how they work in space, then imagine how they would fit in your drawing. Form: You are getting some nice shadows in the face but try pushing those same shadows in the hair. Look at reference of a young mans face and look at all the different planes there are, i'd say you are hitting the basic ones and it could be pushed further. Edges: If you are trying to go for realism, relook at how sharp your edges/outlines are. Push the painting away from lines, especially in the lightest parts. You can try using color and shadows to help with this. If you want to use lines in your drawing, try using different thickness to draw interest into your piece, thicker toward your darks, thinner toward your lights. Hope these tips help! You really aren't that far off.