1) First, what about the background? You can add a cloudy sky for fun, or throw in some trees or some interesting buildings. If your picture is indoors, what could you add in the background? A pet, or some toys or maybe some food? It could be fun to put a bowl of goldfish on a table or a pair of shoes under the bed.
2) Second, you can make things look closer or further away depending on the relationship of size. Something very close looks much bigger than something further away. You can also decide which things are in front of or behind other things. The things in front look bigger and they also block your view of part of what is behind them. Your drawing gets interesting as you arrange the parts by size and decide what’s in front and what’s behind.
3) Third, you can show depth by deciding which direction the light is coming from in your drawing. The side of everything that is closer to the light will look lighter, and the parts of the drawing that will get hardly any light are much darker. You can think about that before you start coloring or painting and decide where the very darkest spot should be. It will be something that gets almost no light—maybe it’s the tiny spaces between the fingers, or maybe it’s the nostrils. If you hold your fingers together, it looks like there is a line between them. There really isn’t, of course, but it looks like it because no light can get between them, so it seems like a dark line.
4) Fourth, you can make your drawing happy or sad or scary by the colors you choose. You could make a garden very bright with yellow-greens and bright flowers and maybe a bright turquoise sky, or you could make the same garden spooky with dark colors and a black sky. Maybe the spooky flowers are dark purple or blue, or you could leave them white so they seem ghost-like.
5) Fifth, you can leave empty spaces that have an interesting shape of their own. If you curve your fingers and put your two hands together at the heels and the tips of your curved fingers, you can make a heart. But the heart is just the empty air between your hands. That’s called a “negative space.” It’s not an object, it’s just the shape in between two or more objects.