One tip for learning to draw dragons is to lay out the skeleton of the dragon first. Placing bones and joints in convincing places make illustrated dragons look more realistic. Another tip is to imagine a plausible muscle structure for the dragon. The underlying muscle determines what the outside of the dragon looks like, and gives the illustrator a shape to follow.
It is important to think about scale type and placement when drawing a dragon. Think about how the dragon moves, attacks and defends itself when choosing where to place scales. Thick, large scales are good for defense, but should not be on wings or other body parts that need to be light to function.
One tip for giving the dragon personality is to use a human face as a reference for the dragon's face. Humans can easily recognize and identify with the emotions of a human face. Combine this familiarity with the scales of a dragon to create a beast that looks intelligent and relatable.
Study reptiles from nature, such as alligators, snakes and lizards, to learn more about reptilian body and facial structure. Note features such as the distance between the eyes and the mouth and the difference in size between the upper and lower jaws. This broadens the illustrator's knowledge of reptiles and can be a source of inspiration.