Heimdall guards the Bifrost. The Bifrost is the spiritual connection to the ancestors (source of what could be called "divine inspiration"). Heimdall is more knowledgeable, has wisdom, and is older than both the Vanir and the Aesir. The name "Heimdall" literally translates to mean "home of world knowledge", add somewhere to his depiction some scrolls to represent a library.
Features to include when drawing:
Gray blue eyes
Very white skin
Older/wise looking but not old man
Muscle tone like Odin
Horn (Gjallarhorn) – looks like a mead horn
Rams horns on his helmet
Heimdall is guardian of the Bifrost, bridge of light and divine path to Asgard
Splash color = Teal
The Bifrost should be depicted as the Aurora Borealis (northern lights) commonly seen in the Nordic region, a shimmering path of light to Asgard.
Heimdall is connected to the old world sea gods Aegir and Ran.
Heimdall represents and personifies, and is the source of what is known as divine inspiration, perspective, and insight as it relates to evolution, and science.