Monocular
1. Motion parallax: distant things move slower; close things move faster.
2. Depth in motion: something coming closer to you gets bigger.
3. Perspective: parallel lines converge as they move away from you.
4. Familiar size: evaluating the position of an object whose size is known.
5. Relative size: comparing the position of an unknown object to one whose size is known.
6. Color and contrast: all else being equal, reds appear closer than blues, and high-contrast colors appear closer than low-contrast colors.
7. Accommodation: whether the eye is focused on a near or far object, as reported by our eye muscles.
8. Occlusion: an object blocking something else is assumed to be in front of it.
9. Depth of field: blurrier objects are assumed to be further away.

Binocular
10. Stereopsis: the difference between the views of the left and right eye.
11. Convergence: the angle from our eyes to the object viewed, as reported by our eye muscles (for objects closer than ~10m).