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Greatly appreciate the tips, and it's always better when you elaborate more on the problems. I'll take this into consideration and try out a new drawing or some sort tomorrow after busy crap.
Edit:
I would also like to clarify that I would like tips to help it look better by addressing issues that would otherwise lower the quality of the colours. I'm not too worried about perfect lighting and shadows, since the main purpose is to make something that looks nice, and sometimes complete accuracy of lighting techniques would be unnecessary and would rather cause more stress for perfection.
Help on perfect lighting, though, would still help me understanding more on how to do it and is welcomed. But I'm still looking for the issues of overall quality, like the hair shine addressed by Otis and Tesla.
Cheers.