Learn to draw cartoons by first looking at an object or person and observing basic shapes and proportions. Take photographs and use them to study details. After deciding what shapes and sizes the objects are, use them as a framework for the drawing.
After noticing the basic shapes in an object, draw them in an arrangement that suggests the structure of the item. For example, a tree is a circle on top of a rectangle. To learn to draw similar things, use the same basic layout but adjust the final details. Use the framework for a cat to draw a lion or a basic dog framework to draw many different breeds.
When drawing a group of items observe proportion and incorporate it into the drawing. A person would not be taller than a tree and a cat would not be bigger than a house. Draw markers to gauge different sizes and remove them when the cartoon is finished. Adjust the proportion as needed.
To make the cartoon unique look for details, such as feathers on birds or leaves on trees. Learn to draw these details by playing with the texture on paper. To make the object look grounded observe the light source and draw shadows on or under the objects.