It can be fun but also challenging to depict the same character showing different emotions, in different settings, while engaging in a variety of activities as well. The character of the giant in The Selfish Giant not only had to do all these things, but he also had to age over time, while undergoing a transformation from gruff and grumpy young man, to playful middle-aged man, and finally kind-hearted and gentle old man.
To develop the character I started by doing tons and tons of thumbnails - some good, many not so good. You'll hear me repeat this a lot: to a large extent art is about quantity, not quality. Sometimes you need to focus to finish and polish a piece, other times you need to just crank out drawings until you get something that looks worth keeping. I drew this character from different angles, showing different expressions, concentrating on the face and head.
When the giant first appears, as a relatively young man, he's got thicker hair, the beginnings of a beard, and smooth, though heavy features. His hands are fairly meaty as well.
Later, after his great epiphany, the giant becomes the jovial playmate of the town's children. He's now middle aged - his hair is a bit thinner and just starting to gray, the flesh on his face is a bit looser, beginning to show some creases, his hands still strong but getting a little thinner, and his now shaved beard makes the lower part of his face appear slightly darker and less saturated.
Finally, as an old man, the giant's stubbly beard has turned white, his hair is even more thinned out, and showing more gray; his face is a bit splotchy, his neck is wrinkled, and his hands are getting quite bony, with more pronounced knuckles and bluish veins showing through here and there:
You can see the full versions of these images, and other Selfish Giant pictures on my website