Draw a small oval for the head
Add a larger oval for the body
Sketch two round ears on top of the head
Draw a pointed snout at the front
Add two small eyes
Draw a tiny nose at the tip of the snout
Add whiskers on both sides of the face
Draw four thin legs under the body
Add small rounded feet
Draw a long thin tail extending from the back
Refine the outline to make the mouse shape smooth
Erase extra guidelines
Add shading or simple details if desired