Night Vision is a skill all ninja should have. Therefore I have compiled 8 tips to help you with your night vision.
1-Protect your night vision. It takes 30 minutes for your eyes to adjust to the dark, but only a few minutes to adjust to the light. And after the point when you have your night vision, anything from the flame from a match to a bright flash can destroy it.
2-Use your peripheral vision. There is a higher rod cell density in your peripheral vision and rods are much more sensitive to light than cones are.
3-Scan the area. If you allow your vision to stay in one place, your eyes may adjust to the little light there is.
4-Rather than looking for color, look for movement, shape, and contour.
5-If it is necessary to use a light, use a dim one with a red filter. Red is the color that is least harmful to your night vision.
6-When moving into an area of light, keep one eye closed and one open so you can keep your night vision active in one eye. This was, in fact, why pirates wore eyepatches.
7-Get lower than the object your looking at. This should allow you to see the contour better.
8-Early astronomers didn't have the high powered telescopes we have now, so they had to use small tubes to look at the sky. Although this wasn't a lot, it cut down the light coming into the eye, regenerating visual purple and reactivating rods. You can use the same technique by making a tube over your eye with your hand.