First, decide on the color scheme. Maybe go for soft pastels for a dreamy look. Start with the skin tone, then move on to the clothes and background. Pay attention to light and shadow to make it look realistic.
You can start by outlining the boy with light colors. Then, fill in the details like his pajamas or blanket with appropriate shades. Add some shading for a 3D effect.
Maybe he's just really tired after a long day of play.
He could be sleeping because it's his bedtime and he needs to rest for the next day's adventures. Or perhaps he had a very exhausting study session.
He could be sleeping because it's his nap time or he stayed up too late last night. Sometimes kids need their rest after having lots of fun.
Maybe he's just really tired from playing all day.
Maybe they're just really tired after a long day of play and adventure.
Maybe he's just really tired and needs a good rest.
Often, in a sleeping boy cartoon, you'll notice that the colors are soft and calming. The boy's face might have a relaxed look, and sometimes there could be little details like a favorite stuffed toy by his side.
Maybe he's playing hide-and-seek and chose the closet as his hiding spot.
The little boy might be sleeping because he didn't get enough sleep the night before. Maybe he was up late watching a movie or reading a book and now needs to catch up on sleep.
Maybe he's just really tired from a long day of play and adventure.